Michael Horton on Union with Christ...

"Union with Christ is not to be understood as a “moment” in the application of salvation to believers. Rather, it is a way of speaking about the way in which believers share in Christ in eternity (by election), in past history (by redemption), in the present (by effectual calling, justification, and sanctification), and in the future (by glorification). Nevertheless, our subjective inclusion in Christ occurs when the Spirit calls us effectually to Christ and gives us the faith to cling to him for all of his riches...

"The motif of mystical union has often been presented as an alternative to the forensic (legal) motifs of redemption, especially vicarious substitution and justification. Since Albert Schweitzer, the thesis has repeatedly been advanced, refuted, and then advanced again that justification is a “subsidiary crater” in Paul, while the real central dogma is mystical union. Reginald Fuller notes, “Attempts have been made to pinpoint some other center or focus for Pauline theology, such as ‘being in Christ’ (Schweitzer) or salvation history (Johannes Munck).” However, “Romans, the most systematic exposition of Paul’s thought, clearly makes justification the center.” Not only in Paul but in the pre-Pauline creedal hymns we find this affirmation (2Ti 1: 9 and Tit 3: 4– 5)...

"Like Schweitzer, a variety of contemporary trends in Pauline studies as well as Reformation scholarship are driven by the presupposition that mystical participation in Christ stands over against a forensic emphasis on Christ’s alien righteousness imputed to believers. 3 Through the interpretive lens of union with Christ we can move beyond the false choice of a legal, judicial, and passive salvation on one hand and a relational, mystical, and transformative participation in Christ on the other. Nevertheless, as I argued in relation to Christ’s atoning work, the integral unity of these motifs is possible only because the latter is grounded in the former. As Geerhardus Vos expressed it,

In our opinion Paul consciously and consistently subordinated the mystical aspect of the relation to Christ to the forensic one. Paul’s mind was to such an extent forensically oriented that he regarded the entire complex of subjective spiritual changes that take place in the believer and of subjective spiritual blessings enjoyed by the believer as the direct outcome of the forensic work of Christ applied in justification. The mystical is based on the forensic, not the forensic on the mystical.

"In Romans 5, the covenantal union of humanity in Adam is contrasted with Christ’s covenantal headship, and then in chapter 6 we encounter his most explicit description of union with Christ in his death and resurrection (Ro 6: 1– 23; cf. 1: 3– 4; 4: 25; 1Co 15: 35– 58). Though they have been “in Christ” in God’s electing grace from all eternity (Eph 1: 4, 11; 2Ti 1: 9), their actual union with Christ occurs in time through the work of the Spirit. Throughout the Pauline corpus we encounter this emphasis on union with Christ."

[bold emphasis added]

Horton, Michael S. (2011-01-04). The Christian Faith: A Systematic Theology for Pilgrims on the Way (Kindle Locations 14544-14565). Zondervan. Kindle Edition.

Calvin: To Admit Sinner into Union with God is to Justify Him...

"Hence the Apostle shows that man is at enmity with God until he is restored to favor by Christ, (Romans 5:8- l 0.) When the Lord, therefore, admits him to union, he is said to justify him, because he can neither receive him into favor, nor unite him to himself, without changing his condition from that of a sinner into that of a righteous man. He adds that this is done by remission of sins. For if those whom the Lord has reconciled to himself are estimated by works, they will still prove to be in reality sinners, while they ought to be pure and free from sin. It is evident therefore, that the only way in which those whom God embraces are made righteous, is by having their pollutions wiped away by the remission of sins, so that this justification may be termed in one word the remission of sins." [emphasis added]

Calvin, John. Institutes: Christian Religion Book 3.9.22

Calvin: Gift of Adoption by which God Admits Us into a Union with Christ...

"though we may be pressed down by adversity, yet we are not excluded from the number of God's children, since we see him going before us who was by nature his only Son; for that we are counted his children is owing only to the gift of adoption by which he admits us into a union with him, who alone lays claim to this honor in his own right." [emphasis added]

Calvin, John. Complete Commentaries, Hebrews 5:7

Calvin: Until Imputation of Righteousness "Union with God Cannot Be Hoped For"

"We yesterday compared this passage of Habakkuk with the interpretation of Paul, who draws this inference, that we are justified by faith without the works of the law, because the Prophet teaches us that we are to live by faith, for the way of life and of righteousness is the same, inasmuch as life is not to be otherwise sought by us than through the paternal favor of God. This then is our life--to be united to God; but this union with God cannot be hoped for by us while he imputes sins to us; for as he is just and cannot deny himself, iniquity must be ever hated by him. Then as long as he regards us as sinners, he must necessarily hold us as hateful to him. Where the hatred of God is, there is death and ruin. It then follows, that we can have no hope of life until we be reconciled to God, and there is no other way by which God can restore us to favor, but by regarding and counting us as just. It hence follows, that Paul reasons correctly, when he leads us from life to righteousness; for they are two things which are connected and inseparable." [emphasis added]

Calvin, John. Complete Commentaries - Habakkuk.

Calvin: Justified, Believer Becomes One with Christ...

"To sum up the whole, this passage, first, teaches us to behold Christ with the eyes of faith; and, secondly, it informs us, that every one who is regenerated by the Spirit, and gives himself up entirely to God for true justification, is thus admitted to the closest union with Christ, and becomes one with him."

Calvin, John. Complete Commentaries - Matthew 12:48

Believers: Dead to the Guilt of Sin - Alive unto Righteousness...

 Even so we also should walk in newness of life., Romans 6:4b. 

It is the purpose of our rising with Christ, that we also, by the glory or power of the Father, 2 Corinthians 13:4, should walk in newness of life. The resurrection of Christ was the effect of the power of God, not in the ordinary way of nature, but of a supernatural exertion of power. In the same manner, believers are raised to walk in newness of life. It is thus that, when Paul, Ephesians 1:20, exalts the supernatural virtue of grace by which we are converted, he compares it to the exceeding greatness of that power by which Christ was raised from the dead. This shows the force of the Apostle’s answer to the objection he is combating. Believers are dead to the guilt of sin, and if so, the ground of their separation from God being removed His almighty power is engaged and asserted to cause them to walk with their risen Lord in that new life which they derive from Him. It was, then, the purpose of Christ’s death that His people should become dead to sin, and alive unto righteousness. ‘Who His own self bare our sins in His own body on the tree, that we being dead to sins, should live unto righteousness,’1 Peter 2:24. On this same ground, when viewing it simply as a motive, Paul reminds believers that since they are dead with Christ, they should set their affections on things above, and not on things on the earth, assuring them that when He who is their life shall appear, then shall they also appear with Him in glory, Colossians 3:4. And again he declares, ‘If we be dead with Him, we shall also live with Him,’ 2 Timothy 2:11.

Robert Haldane, Romans Commentary

Salvation from Sin (1): Christ saves from the guilt of sin

This, and the next 3 posts, are excerpted from the sermon, Salvation from Sin by John Colquhoun, in which he explains the nature and extent of the believer's salvation from sin wrought by the Lord Jesus Christ. An interesting yet important aside is how Colquhoun's understanding of the logical order of legal and mystical union with Christ as well as the logical order of the imputation of Christ's atonement and the believer's justification are interwoven into his explanation of salvation from the guilt of sin.

And here, in the first place, he saves them from the guilt of sin. — By the guilt of sin, is meant an obligation to suffer eternal punishment on account of sin. They whom Christ undertook to save were, on account of their breach of covenant in the first Adam, and of their other innumerable transgressions of the Divine law, condemned as well as the rest of mankind, to endure such tremendous wrath, both in soul and body, as would have rendered them inexpressibly miserable. While, therefore, they continue under the law as a covenant of works, they are necessarily under this dreadful sentence; and were they to die in that state, it would be executed upon them to the uttermost, through the revolving ages of eternity.

"But since they were not appointed to wrath, but to obtain salvation by the Lord Jesus Christ, he comes in the day of regenerating power, and having united them to his person [legal/federal], admits them to actual communion [mystical/experiential] with himself, in his infinitely precious atonement [notice the logical order]. No sooner is this atonement actually imputed to them, than they are legally absolved from condemnation [notice the logical oder - imputation then justification], according to this Divine promise, "I will forgive their iniquity, and I will remember their sin no more," Jer. xxxi. 34. 

"They are then delivered from the guilt of sin, or from their obligation to endure punishment on account of sin, and have sufficient security afforded them, that though they may often incur the guilt of fatherly displeasure, they shall never enter into condemnation, or fall under the guilt of eternal wrath.

- John Colquhoun. Sermon XIV, Salvation from Sin.  

(Bracketed comments and emphasis added)

Imputation - An Union of Representation...

James Buchanan:

"Take the three cases of Imputation which have been specified, and

compare them with one another. We find, that in two out of the three, a change of moral character is the invariable concomitant or consequent of imputation; for the imputation of Adam’s guilt to his posterity, was connected with their loss of original righteousness and the corruption of their whole nature; and the imputation of Christ’s righteousness to His people is connected, in like manner, with their renewal and sanctification; but we also find that, in the third case, —which is as real and as complete an instance of imputation as either of the other two, —the imputation of our sins to Christ was not connected with any change in His holy character, or with the infusion of any, even the slightest’ taint of moral evil; whence we infer that imputation, so far from consisting in, is not even invariably connected with, the infusion of moral qualities. 

• We find again, that in two out of the three cases, representative, and personal, agency are so clearly distinguished as to make it manifest, that the party to whom anything is imputed is not supposed to have had any active participation in the doing of it: for our sins were really, and in the full sense of the term, imputed to Christ as our substitute, yet He had no share in the commission of them; and His righteousness is, in like manner, imputed to us for our Justification, yet we had no share with Him in ‘finishing the work which the Father had given Him to do.’ 

"—Whence we infer that, in the third case, —that of the imputation of Adam’s guilt to his posterity, —it is so far from being necessary to suppose our personal participation in his act, that such a supposition would go far to destroy the doctrine of Imputation altogether, by setting aside the fundamental distinction between the agency of the representative, and that of those who were represented by him. 

"We find, again, that in all the three cases, imputation, whether of sin or of righteousness, is founded on a federal relation subsisting between one and many, —for Adam was constituted the head and representative of his race, and Christ the substitute and surety of His people; and that this relation may be fitly described as amounting to a union between them, in virtue of which they are regarded and treated as being, in some respects, one; but that this union is not such as to destroy the distinction between their respective personalities, or to confound their several acts: for it is still true, that the representative was personally different from those whom he represented, and that his obedience, or disobedience, was his own act, and not theirs, although it is imputed to them; for ‘a union of representation is not a union of identity.’ ‘No imputation of this kind,’ says Dr. Owen, speaking of the imputation of anything that was not ours antecedently, but that becomes ours simply by being imputed, —‘is to account them, unto whom anything is imputed. to have done the things themselves which are imputed unto them… . This is contrary unto the nature of imputation, which proceeds on no such judgment, but on the contrary, (implies) that we ourselves have done nothing of what is imputed unto us, nor Christ anything of what is imputed unto Him.’"

James Buchanan. The Doctrine of Justification

Romans 6 Intro: Intimate connection between justification and sanctification - eternal life the gift of God

Robert Haldane: Commentary on Romans, Chapter Six.

Introduction
IN the preceding part of the Epistle the universal depravity and guilt of man, and the free salvation through the blood of the Lord Jesus Christ, had been fully exhibited. Paul now proceeds to prove the intimate connection between the justification of believers and their sanctification. He commences by stating an objection which has in all ages been advanced as an unanswerable argument against salvation by grace. He asks, What is the consequence of the doctrine he has been inculcating? If justification be bestowed through faith, without works, and if, where sin abounded, grace has much more abounded, may we not continue in sin that grace may abound? No objection could be more plausible. It is such as will forcibly strike every natural man, and is as common now as it was in the days of the Apostle. 

Paul repels this charge by declaring the union of believers with Jesus Christ, by whom, as is represented in baptism, His people are dead to sin, and risen with Him to walk in newness of life. Having established these important truths, he urges (ver. 11) on those whom he addresses the duty of being convinced that such is their actual state. In verses 12 and 13, he warns them not to abuse this conviction; and for their encouragement in fighting the good fight of faith, to which they are called, assures them, in the 14th verse, that sin shall not have dominion over them, because they are not under the law but under grace. Thus the Apostle proves that, by the gracious provision of the covenant of God, ratified by the blood of Him with whom they are inseparably united, they who are justified cannot continue to live in sin; but though sin shall not have dominion over them, still, as their sanctification is not yet perfect, he goes on to address them as liable to temptation. What he had said, therefore, concerning their state as being in Christ, did not preclude the duty of watchfulness; nor, since they had formerly been the servants of sin, of now proving that they were the servants of God, by walking in holiness of life. Paul concludes by an animated appeal to their own experience of the past, and to their prospects for the future. He asks, what fruit had they in their former ways, which could only conduct to shame and death? On the other hand, he exhorts them to press onwards in the course of holiness, at the end of which they would receive the crown of everlasting life. But, along with this assurance, he reminds them of the important truth, that while the just recompense of sin is death, eternal life is the gift of God, through Jesus Christ our Lord.

Sanctification (3), "a native consequence of union with the second Adam, of justification, reconciliation, and adoption"

John Colquhoun discusses sanctification in relation to union with Christ and justification:

7th, It is a native consequence of union with the second Adam, of justification, reconciliation, and adoption. — It is a fruit of vital union with Christ. By vital union with him, we become members of his mystical body, of that body to which he is united, as the glorious Head of sanctifying influences; but as the head is holy, the members must be holy also. Besides, they who are united to Christ are in him; but all who are in Christ are sanctified. "To them that are sanctified in Christ Jesus," 1 Cor. i. 2. In virtue of this union, the believer lives in Christ, and Christ in him: he partakes of the same Spirit that dwells in Christ. 

It is a necessary fruit of justification, and inseparably connected with it. It is connected with it in the decree and promise of God, in the offices of Christ, and the design of his obedience unto death. When the blood of Christ is sprinkled on our conscience for justification, it has a special efficacy for sanctification. It purges the conscience from dead works, and then the believing sinner is enabled to serve the living God. "The blood of Jesus Christ his Son cleanseth us from all sin." The sprinkling, or application of the blood of Jesus, has a sanctifying efficacy; for it removes the curse of the law which is the strength of sin, and which hinders the acceptance, both of the sinner's person and performances. When this is done, the dominion of sin is taken away: its power and pollution begin to be gradually removed. Hence are these reviving expressions; "Sin shall not have dominion over you: for ye are not under the law, but under grace." Christ hath redeemed us from the curse of the law, — that we might receive the adoption of sons, and that we might receive the promise of the Spirit through faith. 

It is also a fruit of reconciliation. No sooner does the sinner begin to have peace with God in Christ, as one reconciled to him, than a way of free communication is opened between Christ the head of influences, and his soul. Besides, the sanctifying efficacy of the blood of Christ arises from its atoning or pacifying virtue, Heb. ix. 14. 

It necessarily follows adoption. "Because ye are sons, God hath sent forth the Spirit of his Son into your hearts, crying, Abba, Father." "Whom he did foreknow, he also did predestinate to be conformed to the image of his Son; that he might be the first-born among many brethren," Rom. viii. 29.

John Colquhoun. Sermons, chiefly on doctrinal subjects, 171-72

In other words...

Union with Christ has the double-benefit of justification and sanctification. But the hallmark of an early modern Reformed doctrine of union with Christ is according theological priority to justification over sanctification, or priority of the forensic over the renovative. Another way to say this is that justification is the legal basis of a believer's redemption. Or still yet, a person can say, "I am sanctified because I am justified." But he cannot say, "I am justified because I am sanctified." - John Fesko. Beyond Calvin: Union with Christ and Justification in Early Modern Reformed Theology (1517-1700), pp 29-30

How shall man be just with God?

"From what has been stated, we may learn a satisfactory answer to this question, How shall man be just with God? How can an unrighteous person be accepted as righteous by an infinitely righteous Judge? It can not possibly be on the ground of his own performances; for though he should even from the moment of his birth till that of his death, obey the law perfectly, it could never satisfy for the sin in which he was born. It is by the consummate righteousness of Jesus Christ received by faith, that he can be just in the eye of the law, or the sight of God. 

"Hence learn, that the righteousness which is the ground of a sinner's justification, is not the believer's because it is imputed to him; but it is imputed to him because it is already his. In God's imputation of it, he reckons it to be what it is already, the believer's justifying righteousness. It is the believer's, in virtue of his legal union with Christ from eternity, and of his vital union with him in time."

John Colquhoun. Sermons - Chiefly on Doctrinal Subjects, 160.

Righteouseness imputed to believer "because it is already his" - John Colquhoun

"From what has been stated, we may learn a satisfactory answer to this question, How shall man be just with God? How can an unrighteous person be accepted as righteous, by an infinitely righteous Judge? It can not possibly be on the ground of his own performances; for though he should even from the moment of his birth till that of his death, obey the law perfectly, it could never satisfy for the sin in which he was born. It is by the consummate righteousness of Jesus Christ received by faith, that he can be just in the eye of the law, or the sight of God. 

"Hence learn, that the righteousness which is the ground of a sinner's justification, is not the believer's because it is imputed to him; but it is imputed to him because it is already his. In God's imputation of it, he reckons it to be what it is already, the believer's justifying righteousness. It is the believer's, in virtue of his legal union with Christ from eternity, and of his vital union with him in time.

"See also the glorious design of Jehovah in imputing the surety-righteousness of Jesus Christ to his spiritual seed. It is that you, believer, may live; may have a legal right to spiritual, temporal, and eternal life. Your sin was imputed to Christ that he might die: his righteousness is imputed to you that you may live."

John Colquhoun, Sermon IX - Justification

Priority of Justification in Good Works

10. In this way we can admit not only that there is a partial righteousness in works, (as our adversaries maintain,) but that they are approved by God as if they were absolutely perfect. If we remember on what foundation this is rested, every difficulty will be solved. The first time when a work begins to be acceptable is when it is received with pardon. And whence pardon, but just because God looks upon us and all that belongs to us as in Christ? Therefore, as we ourselves when engrafted into Christ appear righteous before God, because our iniquities are covered with his innocence; so our works are, and are deemed righteous, because every thing otherwise defective in them being buried by the purity of Christ is not imputed. Thus we may justly say, that not only ourselves, but our works also, are justified by faith alone. Now, if that righteousness of works, whatever it be, depends on faith and free justification, and is produced by it, it ought to be included under it and, so to speak, made subordinate to it, as the effect to its cause; so far is it from being entitled to be set up to impair or destroy the doctrine of justification that it is what it is.

John Calvin, Institutes of Religion - Book 3.17.10

In Search of Union...

Do a word search for union in your bible and see what you come up with. I did one with my Concordance app (ASV) on my iPad and interestingly enough, though not surprisingly, didn't come up with one single

occurrence of the word. Yet union is a word that today litters Christian essays, articles, sermons, and books. I use the verb 'litters' not to belittle the proper use of the doctrine, but to highlight what I think is often its overuse as the supposed overarching meta-soteriological doctrine explaining salvation in the New Testament.

To me, it seems safest and most helpful to stick with bibilical language as much as possible. "Our union with Christ" or speaking of any particular blessing as coming to us "through union with Christ" aren't incorrect concepts per se. It's just that they are often used so broadly and freely that they are open to misunderstanding especially when not nailed down. As is often asked - what "union" are we talking about? Federal, legal, mystical...? What does one mean by "through union with Christ?"

I think it's similar in some ways to those who would insist that the doctrine of election be front and center when the gospel is preached. Only the elect 'hear' the gospel with ears of faith, yet they don't necessarily need to know up front how and why that is true in order to trust in Christ for forgiveness of sins. That said, the gospel doesn't claim that God sent Jesus to die for everyone and thus make it theoretically possible for everyone to be saved if only everyone would believe. Christ came for the elect. "All that the Father gives me will come to me, and whoever comes to me I will never cast out (John 6:37). Again, the biblical language should be our guide. See examples of gospel preaching in Acts. Is divine election present in the gospel? Indeed, it is the ground, yet most often in the background. 

The doctrine of our union with Christ is central in salvation. As John Calvin wrote,  "so long as we are without Christ and separated from him, nothing which he suffered and did for the salvation of the human race is of the least benefit to us" (Institutes 3.1.1). Yet as a doctrine it remains most often in the background not the foreground when Christ crucified is preached. In a word, faith isn't directly engaged by preaching "our union with Christ", especially when it isn't unpacked. That is how I'm presently thinking about this.

Unpacking "union with Christ" - from R. Scott Clark at Heidelblog:

Definitions

There is also apparently some confusion about what is meant by “union with Christ.” This is understandable because the doctrine has three or four aspects and, in contemporary discussion, all participants have not always been as cautious as necessary to make sure we are talking about the same aspect at the same time in the same way.

Louis Berkhof (1873–1957) represented the mainstream of the Reformed tradition when he spoke of the “federal union” that all the elect have with Christ (Systematic Theology, 448). This aspect of union is relative to the eternal, pre-temporal (before time) “covenant of redemption” (pactum salutis) between the Father and the Son (and the Holy Spirit). According to Ps 110, John 17 and other passages, the Father gave to his Son a people and the Son volunteered to be their Mediator, their federal representative, and their Savior; i.e., to earn their salvation. This is one of the three or four aspects of our union with Christ. For more on this see the chapter on the “Covenant Before the Covenants” in Covenant, Justification, and Pastoral Ministry.

Berkhof wrote of a second aspect of our union with Christ, which he called the “union of life” (ibid). This union refers to the natural, organic relation that all humans have with the first Adam, who was the federal representative of all humanity (Rom 5). The corollary to our natural union with Adam, in whom we would have entered in glorious life had he (and we in him) obeyed the commandment of life (“you shall not eat”). In the covenant of redemption God constituted a union between the Son, who would be the Last Adam (1Cor 15) and his people. Implicitly, the Holy Spirit was a party to this covenant as that person who would apply redemption to the people given to the Son. The Second Adam (Rom 5), Jesus, fulfilled that covenant of works for all those whom he represented, for whom he died and for whose justification he was raised.

We might also speak of a third aspect of our union with Christ, which we might call decretal union, i.e., the union that exists between Christ and his people by virtue of God’s decree to elect, in Christ, some out of the mass of fallen humanity to redemption. Paul spoke to this aspect of our union with Christ when he wrote that we were chosen “in Christ” before the foundations of the world (Eph 1). This aspect is, of course, a corollary to the federal union and the union of life mentioned above.

The last aspect is mystical union (or sometimes referred to as “existential union”) and it refers to the subjective application of redemption purposed from eternity in the decree, covenanted among the Trinitarian person in the pactum salutis, accomplished by Christ in his active and suffering obedience, and applied to the elect by the Holy Spirit. Mystical union is, as Berkhof put it, that “intimate, vital, and spiritual” connection “between Christ and his people, in virtue of which He is the source of their life and strength, of their blessedness and salvation” (Systematic Theology, 449).

And also...

That faith which secures eternal life; which unites us to Christ as living members of his body; which makes us the sons of God; which interests us in all the benefits of redemption; which works by love, and is fruitful in good works; is founded, not on the external or the moral evidence of the truth, but on the testimony of the Spirit with an by the truth to the renewed soul (Systematic Theology, 3.68).

…The first effect of faith, according to the Scriptures is union with Christ. We are in him by faith. There is indeed a union between Christ and his people, founded on the covenant of redemption between the Father and the Son in the counsels of eternity. We are, therefore, said to be in Him before the foundation of the world.

…But it was also, as we learn from the Scriptures, included in the stipulations of that covenant, that his people, so far as adults are concerned, should not receive the saving benefits of that covenant until they were united to Him by a voluntary act of faith. They are ‘by nature the children of wrath, even as others.’ (Eph. ii.3) They remain in this state of condemnation until they believe. Their union is consummated by faith. To be in Christ, as to believe in Christ are, therefore , in the Scriptures, convertible forms of expression. They mean the same thing, and therefore, the same effects are attributed to faith as are attributed to union with Christ” (Ibid, 3.104)

 So says Charles Hodge (1797–1878), who taught at Old Princeton for about fifty years, on the relation between faith and union.

Justification & Union with Christ: Clearing up the Confusion

From J. V. Fesko's article A More Perfect Union: Justification and Union With Christ:

Bishop and Pauline scholar N. T. Wright is well-known for his rejection of the doctrine of the imputed righteousness of Christ. He argues that everything that one would receive through imputation, one receives through union with Christ. Union with Christ makes imputation a redundancy. While Wright does not specifically state it in these terms, his rejection of imputation seems to rely upon the older tendency pointed out above, to subsume the order of salvation (ordo salutis) to union with Christ. Wright, for example, argues that the Reformed understanding of the order of salvation, while perhaps reflective of the Reformed tradition, is not necessarily reflective of Paul's theology. Rich Lusk, a former Presbyterian Church in America (PCA) and current Confederation of Reformed Evangelical Churches (CREC) pastor, has a similar understanding of the relationship between justification and union with Christ.

Lusk also sees a conflicting tension between the legal and relational categories in traditional Reformed theology: "The covenant of works construction strikes at the filial nature of covenant sonship. Adam was God's son, not his employee." Given the supposed incompatibility of the legal and relational, it should be no surprise that Lusk allows the believer's union with Christ to swallow legal aspects of the believer's justification:

"This justification requires no transfer or imputation of anything. It does not force us to reify "righteousness" into something that can be shuffled around in heavenly accounting books. Rather because I am in the Righteous One and the Vindicated One, I am righteous and vindicated. My in-Christ-ness makes imputation redundant. I do not need the moral content of his life of righteousness transferred to me; what I need is a share in the forensic verdict passed over him at the resurrection. Union with Christ is therefore key."

Here Lusk argues that union with Christ makes legal elements of the believer's justification redundant and unnecessary, specifically that of the imputed active obedience of Christ....

... The Reformed tradition bases the doctrine of the imputed righteousness of Christ, even his active obedience, on such passages as Romans 5:12-21 (WCF 6.3, 11.1; cf. Heidelberg Catechism, Q/A 60). Why, for example, does Paul contrast the disobedience of Adam with the obedience of Christ? Paul writes, "For as by the one man's disobedience the many were made sinners, so by the one man's obedience the many will be made righteous" (Rom. 5:19). As John Murray explains, "The parallel to the imputation of Adam's sin is the imputation of Christ's righteousness. Or to use Paul's own terms, being 'constituted sinners' through the disobedience of Adam is parallel to being 'constituted righteous' through the obedience of Christ." Clearly, Romans 5:19 restates what Paul has stated in the previous verse: "Therefore, as one trespass led to condemnation for all, so one act of righteousness leads to justification and life for all" (Rom. 5:18).

There is no mistaking the parallel between Christ's obedience, which is righteousness, and the imputation of this righteousness to the believer. Commenting on the abiding significance of Genesis 15:6 and the imputation of righteousness, Paul writes: "That is why his faith was 'counted to him as righteousness.' But the words 'it was counted to him' were not written for his sake alone, but for ours also. It will be counted to us who believe in him who raised from the dead Jesus our Lord" (Rom. 4:22-24). Note here the English Standard Version translates the Greek word logizomai as "counted," which the King James Version translates as "imputed." Here Paul taps into the ancient stream of the special revelation of the Pentateuch, the first five books of the Bible, to argue for the imputed righteousness of Christ, and arguably also has other passages such as Isaiah 53 in mind when writing these things: "Out of the anguish of his soul he shall see and be satisfied; by his knowledge shall the righteous one, my servant, make many to be accounted righteous, and he shall bear their iniquities" (Isa. 53:11; cf. 2 Cor. 5:19-21).

We should also note, however, that in all of Paul's argumentation for his doctrine of justification and especially the imputed active obedience of Christ, he can write everything that we have surveyed, and at the same time also write without qualification or wincing: "There is therefore now no condemnation for those who are in Christ Jesus" (Rom. 8:1). If condemnation is the antonym for justification, then we can also reword Romans 8:1 to say, "There is therefore now justification for those who are in Christ Jesus" (emphasis added). In other words, a robust doctrine of justification that includes the imputed active and passive obedience of Christ is not antithetical to our union with Christ, nor is it superfluous. Rather, it is the legal aspect of our union with Christ. As A. A. Hodge explains, our union with Christ has a federal and representative character. Once again, what God has joined together, let man not separate. This brings us to one last element to consider, namely that justification is the ground of our sanctification...

...In terms of union with Christ and justification, Berkhof therefore explains that "justification is always a declaration of God, not on the basis of an existing condition, but on that of a gracious imputation-a declaration which is not in harmony with the existing condition of the sinner. The judicial ground for all the special grace which we receive lies in the fact that the righteousness of Christ is freely imputed to us." What we must realize, then, is that the ground of our redemption is the work of Christ; correlatively, we should also recognize that the ground of our sanctification is our justification. In other words, apart from the legal-forensic work of Christ, received by imputation through faith, there is no transformative work of the Holy Spirit. Or, using the title of John Murray's famous book, apart from redemption accomplished, there can be no redemption applied (see WCF 11.3; Larger Catechism, Q/A 70).

The entire essay can be read at Modern Reformation.

Some Thoughts on Union, Gospel, Faith...

The phrase – union with the resurrected Christ by faith is the central motif of Paul’s applied soteriology (Gaffin, OPC, Resurrection and Redemption, p 132) – is a debatable notion and one that arguably can lead in a subjective direction depending on its use and emphasis. Why? Because the phrase union with Christ as it is often used tends to point towards accessing something within me rather than appropriating by faith something without me and done for me. ‘Union with Christ’ as a central motif for the believer tilts one toward the experiential/positional as the focus for Christian living as opposed to the legal or forensic (election/federal) in which the elect are identified as ‘in Christ’ their Surety (Eph 1:3; Rom 6:3-5). My concern is that the focus on union unwittingly causes the eye to turn to one's inward experience of sanctity rather than to the finished work of Christ, the object of our faith - something outside of us and our experience - the good news of Jesus Christ which is the message that

to him who does not work but believes on Him who justifies the ungodly, his faith is accounted for righteousness, just as David also describes the blessedness of the man to whom God imputes righteousness apart from works (Rom 4:5-6)

The power of salvation is in that message – the gospel. And it is that message of justification received through faith,  looking to Jesus Christ and not our experience, that communicates Christ and all his benefits. Justified through faith we are united to Christ by that same faith. But the focus of our faith isn’t our union with Christ. We are united to Christ through faith in him. Faith, enlivened in us by the Spirit's effectual call, looks to Christ. Imputed with Christ's righteousness we are justified through faith and united to him.

Walter Marshall (The Gospel Mystery of Sanctification):

“Therefore, saving faith must necessarily contain two acts, believing the truth of the gospel, and believing on Christ, as promised freely to us in the gospel, for all salvation. By the one, it receives the means in which Christ is conveyed to us; by the other, it receives Christ Himself, and His salvation in the means, as it is one act to receive the breast or cup in which milk or wine are conveyed, and another act to suck the milk in the breast and to drink the wine in the cup… Blessed are they that hunger and thirst after righteousness, for they shall be filled (Matt. 5:6). The former of these acts does immediately unite us to Christ, because it is terminated only on the means of conveyance, the gospel; yet it is a saving act, if it be rightly performed, because it inclines and disposes the soul to the latter act, whereby Christ Himself is immediately received into the heart. He that believes the gospel with hearty love and liking, as the most excellent truth, will certainly with the like heartiness believe on Christ for salvation.”

The means of communicating salvation to dead sinners and nourishing God's people is the gospel which is news of a divine historical event having nothing directly to do with our subjective experience. And the gospel message is not the message of our union with Christ, which faith cannot properly have as its object. The object of faith is Christ Jesus alone and what he did to save the elect. He is the good news of God's redemptive act of  grace for sinners accomplished on the cross. And he is received by the gift of faith as God effectually calls each one. Through believing the good news that Christ died for sinners, one believes not only the good news of forgiveness and righteousness imputed through faith alone but at the same time receives Christ himself. Trusting in Christ as he is presented in the gospel, by the working of the Holy Spirit, believers are united to Christ. Look away with the eyes of faith to Jesus alone, the author and perfecter of faith.

WSC Q. 86. What is faith in Jesus Christ?
A. Faith in Jesus Christ is a saving grace, whereby we receive and rest upon him alone for salvation, as he is offered to us in the gospel.

Justification: Basis is Imputation not Union...

Louis Berkhof:

“It is sometimes said that the merits of Christ cannot be imputed to us as long as we are not in Christ, since it is only on the basis of our oneness with Him that such an imputation could be reasonable. But this view fails to distinguish between our legal unity with Christ and our spiritual oneness with Him, and is a falsification of the fundamental element in the doctrine of redemption, namely, of the doctrine of justification. Justification is always a declaration of God, not on the basis of an existing (or future) condition, but on that of a gracious imputation–a declaration which is not in harmony with the existing condition of the sinner.” (systematic, p 452)

Union with Christ - context...

John 16:27 - For the Father himself loveth you, because you have loved me, and have believed that I came out from God.

To fit the doctrine of our union with Christ into the order of salvation presents a bit of a challenge, to say the least. Phrases such as in Christ, in Him, in the Beloved, Christ in you - all pointing to union - take on different textures of meaning when considered in the context of passages in which they're located. It's in that light that I find helpful the following section from John Calvin's commentary on John. He interrelates concepts such as God's fatherly love for the elect before creation, God's love in Christ for us while yet enemies, God's effectual call, the faith which embraces Christ, and our union with God through Christ. As I understand it, these are various threads of God's identification with his people - those he chose in the Beloved and redeemed in Christ - all pointing to different shades of God's union with his people.

These words remind us that the only bond of our union with God is, to be united to Christ; and we are united to him by a faith which is not feigned, but which [union] springs from sincere affection, which he describes by the name of love; for no man believes purely in Christ who does not cordially embrace him, and, therefore, by this word he has well expressed the power and nature of faith. But if it is only when we have loved Christ that God begins to love us, it follows that the commencement of salvation is from ourselves, because we have anticipated the grace of God. Numerous passages of Scripture, on the other hand, are opposed to this statement. The promise of God is, I will cause them to love me; and John says, Not that we first loved Him, [105] (1 John 4:10.) It would be superfluous to collect many passages; for nothing is more certain than this doctrine, that the Lord calleth those things which are not, (Romans 4:17) raises the dead, (Luke 7:22,) unites himself to those who were strangers to him, (Ephesians 2:12,) makes hearts of flesh out of hearts of stone,   (Ezekiel 36:26,) manifests himself to those who do not seek him, (Isaiah 65:1; Romans 10:20.) I reply, God loves men in a secret way, before they are called, if they are among the elect; for he loves his own before they are created; but, as they are not yet reconciled, they are justly accounted enemies of God, as Paul speaks,     

• When we were enemies, we were reconciled to God by the death of his Son, (Romans 5:10.)    

On this ground it is said that we are loved by God, when we love Christ; because we have the pledge of the fatherly love of Him from whom we formerly recoiled as our offended Judge.

God loves sinners in Christ alone...

From Calvin's 4th sermon on Ephesians. Ch. 1:7-10.

I have shown already that we cannot be loved by God, but by means of his only Son. For if the angels of heaven are not worthy to be taken for God’s children except through a head and mediator, what all become of us who do not cease daily to provoke God’s wrath by our iniquities [Isa. 59:2]. In fact, we fight against him! God, then, must of necessity look upon us in the person of his only Son, or else he is bound to hate and abhor us. In short, our sins set such a distance between God and us, that we cannot approach him without immediately feeling his majesty against us, armed, as it were, to destroy us all...

He confirms the thing in better fashion still by saying that the same was done in Jesus Christ. If we had been elected in ourselves it might be said that God had found in us some secret virtue unknown to men. But seeing that he has elected us outside of ourselves, that is to say, loved us outside of ourselves, what shall we reply to that? If I do a man good, it is because I love him. And if the cause of my love is sought, it will be because we are alike in character, or else for some other good reason. But we must not imagine anything similar to this in God. And also it is expressly told us here, for St. Paul says that we have been elected in Jesus Christ. Did God, then, have an eye to us when he vouchsafed to love us? No! No! for then he would have utterly abhorred us. It is true that in regarding our miseries he had pity and compassion on us to relieve us, but that was because he had already loved us in our Lord Jesus Christ. God, then, must have had before him his pattern and mirror in which to see us, that is to say, he must have first looked on our Lord Jesus Christ before he could choose us and call us...

Therefore we have to observe, first of all, that we can obtain no grace at God’s hand, nor be received by him, till our sins are wiped out and the remembrance of them completely erased. The reason for this is (as I said before) that God must hate sin where-ever he sees it. So then, as long as he considers us as sinners, he must needs abhor us, for there is nothing in us or in our own nature but all manner of evil and confusion. We are, then, enemies to him, and he is contrary to us, till we come to this remedy that St. Paul shows us here, which is, to have our sins forgiven. We see by this that no man can be loved by God because of any worthiness that is in himself. For wherein lies the love that God bears us I have told you already that he must be willing to cast his eye upon our Lord Jesus Christ and not look at us at all.

Me: Calvin states that apart from viewing and accepting us in the person of his Son, God is bound to hate and abhor us due to our innate sinfulness and rebellious nature. Apart from Christ we are rightfully abhorred by God because we, in and of ourselves, are opposed to his righteousness and rule. It is the lack of grasping even an inkling of both the majestic holiness of God and the enormity of our moral corruption that so confounds us in this matter. Even now as his children, adopted of the Father and sealed by his Spirit, there is no inherent quality originating within us that commends us to him. He accepts and loves us solely because in mercy he identifies us in his Beloved Son. God, who chose us in him before the foundation of the world, established irrevocably that he would know and love us only in and through the person and finished work of Jesus Christ. For it is Jesus alone who bore the penalty of our sins thus wiping our slate clean. And it is Jesus who alone is well-pleasing to the Father. To be identified in him is to be loved of God.

Active Obedience - Imputed Righteousness

Tullian Tchividjian's recent post, Cheap Law, at Gospel Coalition sparked quite a debate regarding the relationship of Jesus' perfect obedience and suffering and the righteousness that is imputed to believers through faith.  Not a few think that Christ's forgiveness of sins is alone the basis for the righteousness counted toward his people.  And that that righteousness isn't Christ's imputed but that which comes to us based on forgiveness and being united to Christ.  I chimed in to the vigorous debate and, as is the often the case, I don't think any minds were changed one way or the other.  But to carry on the argument I was making, here is an excerpt from an article, A More Perfect Union - Justification and Union with Christ,  by John Fesko.  It can be read in its entirety at Modern Reformation:

The Reformed tradition bases the doctrine of the imputed righteousness of Christ, even his active obedience, on such passages as Romans 5:12-21 (WCF 6.3, 11.1; cf. Heidelberg Catechism, Q/A 60). Why, for example, does Paul contrast the disobedience of Adam with the obedience of Christ? Paul writes, "For as by the one man's disobedience the many were made sinners, so by the one man's obedience the many will be made righteous" (Rom. 5:19). As John Murray explains, "The parallel to the imputation of Adam's sin is the imputation of Christ's righteousness. Or to use Paul's own terms, being 'constituted sinners' through the disobedience of Adam is parallel to being 'constituted righteous' through the obedience of Christ." Clearly, Romans 5:19 restates what Paul has stated in the previous verse: "Therefore, as one trespass led to condemnation for all, so one act of righteousness leads to justification and life for all" (Rom. 5:18).

There is no mistaking the parallel between Christ's obedience, which is righteousness, and the imputation of this righteousness to the believer. Commenting on the abiding significance of Genesis 15:6 and the imputation of righteousness, Paul writes: "That is why his faith was 'counted to him as righteousness.' But the words 'it was counted to him' were not written for his sake alone, but for ours also. It will be counted to us who believe in him who raised from the dead Jesus our Lord" (Rom. 4:22-24). Note here the English Standard Version translates the Greek word logizomai as "counted," which the King James Version translates as "imputed." Here Paul taps into the ancient stream of the special revelation of the Pentateuch, the first five books of the Bible, to argue for the imputed righteousness of Christ, and arguably also has other passages such as Isaiah 53 in mind when writing these things: "Out of the anguish of his soul he shall see and be satisfied; by his knowledge shall the righteous one, my servant, make many to be accounted righteous, and he shall bear their iniquities" (Isa. 53:11; cf. 2 Cor. 5:19-21).

And Charles Spurgeon eloquently makes the case for the indispensable connection between Jesus Christ's perfect obedience and his righteousness imputed to us:

The promises in the Word of God are not made to suffering; they are made to obedience. Consequently, Christ’s sufferings, though they may remove the penalty of sin, do not alone make me the inheritor of the promise. “If You will enter into life,” said Christ, “keep the commandments” (Matthew 19:17). It is only Christ’s keeping the commandments that entitles me to enter life. “The Lord is well pleased for his righteousness’ sake; he will magnify the law, and make it honorable” (Isaiah 42:21). I do not enter into life by virtue of His sufferings – those deliver me from death, those purge me from filthiness; but entering the enjoyments of the life eternal must be the result of obedience. As it cannot be the result of mine, it is the result of His, which is imputed to me….See what Christ has done in His living and His dying, His acts becoming our acts and His righteousness being imputed to us, so that we are rewarded as if we are righteous, while He was punished as though He had been guilty.
Justification then comes to sinners as an act of pure grace, the foundation of it being Christ’s righteousness. The practical way of its application is by faith. The sinner believes God and believeth that Christ is sent of God. [He] takes Christ Jesus to be his only confidence and trust; and by that act, he becomes a justified soul. It is not by repenting that we are justified, but by believing; it is not by deep experience of the guilt of sin; it is not by bitter pangs and throes under the temptations of Satan; it is not by mortification of the body, nor by the renunciation of self; all these are good, but the act that justifieth is a look at Christ. We, having nothing, being nothing, boasting of nothing, but being utterly emptied, do look to Him Whose wounds stream with the life-giving blood. As we look to Him, we live and are justified by His life. There is life in a look at the crucified One—life in the sense of justification.