Thoughts on Sanctification (Assurance in Our Sanctification)...

[from 2017]

WSC Q. 35. What is sanctification?Sanctification is the work of God’s free grace, whereby we are renewed in the whole man after the image of God, and are enabled more and more to die unto sin, and live unto righteousness.

WCF 13.1 Of Sanctification:  They who are effectually called and regenerated, having a new heart and a new spirit created in them, are further sanctified, really and personally, through the virtue of Christ's death and resurrection, by his Word and Spirit dwelling in them; the dominion of the whole body of sin is destroyed, and the several lusts thereof are more and more weakened and mortified, and they more and more quickened and strengthened, in all saving graces, to the practice of true holiness, without which no man shall see the Lord.

Thoughts on the above: 
By the indwelling of the Word and Holy Spirit, through the virtue of the benefits of Christ's death and resurrection, believer's are really and personally further sanctified, i.e. renewed to the image of Christ and set apart unto righteousness; the result of regeneration which has created in us a new heart and new spirit (or as the English reformer Thomas Cranmer wrote - a new heart and "new right-will"). The dominion of sin is broken because the body of sin (all our guilt and sins) that stood against us has been nullified by Christ's payment for sin on our behalf. Condemnation and Death because of Sin no longer have any claim on those who are Christ's. By His Word and Spirit we are then enabled to grow in this free saving grace (the benefits of Christ's death and resurrection) and, yes, the domininion of sin is overthrown and its power weakened by Christ's death and resurrection through faith alone in him, his mediation. The "more and more" of WCF 13.1 is qualified by the second and third article of WCF 13:

This sanctification is throughout in the whole man, yet imperfect in this life: there abideth still some remnants of corruption in every part, whence ariseth a continual and irreconcilable war, the flesh lusting against the Spirit, and the Spirit against the flesh... In which war, although the remaining corruption for a time may much prevail.

Christ's death on our behalf, paying our penalty due to our sin, is completely and eternally effectual for us. We died in his death to sin. Therefore we paid the penalty for our sin through Christ, our Surety's death for us. 

Rom. 6:6 - knowing this, that our old man was crucified with him, that the body of sin might be done away, that so we should no longer be in bondage to sin.

The legal body of condemning evidence against the elect is done away! Sin can no longer be held up by the Law before God to condemn us. The Law's charge of guilty rightly due to our sin has been removed as far as the east is from the west through our "death" in Christ on the cross. 

When you were dead in your transgressions and the uncircumcision of your flesh, He made you alive together with Him, having forgiven us all our transgressions, having canceled out the certificate of debt consisting of decrees against us, which was hostile to us; and He has taken it out of the way, having nailed it to the cross (Col. 2:13-14).  

When condemnation does creep into my conscience the only safe harbor, then, is not in perfecting my works, but in the Gospel of Christ, the good news encapsulated in Jesus's last words on the cross, "It is finished."

We never (in this life or the next) cease to be the recipients of a fully gracious, God initiated and fully enacted salvation.  

The Bottom Line: Our Father in heaven is not looking for a remedy for the sins of the elect, the impurity of their fallen nature, or the remnant of sin which remains in their every thought, word, and deed other than that wrought by Christ. Hello... Good News... without qualification! 

If God's loving, gracious, and merciful salvation of sinners completed in Christ Jesus needs to be fortified by a purity born of our efforts against sin or pursuing godly works then this Good News of God will soon be replaced by either Despair or Self-Righteousness.

And to aid us in rightly responding to this abundant grace of God we find given to us by the Holy Spirit a new inward and godly desire, born of above, to present ourselves no longer as slaves to sin but slaves to righteousness. And this is why our remaining sin so continues to vex us (Rom. 7 and Gal. 5}! 

So, having then been saved in order that we might be conformed to Christ's image, we're admonished and encouraged by the apostle Paul:

Therefore do not let sin reign in your mortal body so that you obey its lusts, and do not go on presenting the members of your body to sin as instruments of unrighteousness; but present yourselves to God as those alive from the dead, and your members as instruments of righteousness to God. For sin shall not be master over you, for you are not under law but under grace. (Rom. 6:12-14)

Then, as the apostle Paul wrote, let us yield ourselves to the rule of Christ with faith and gratefulness and walk in the path of his righteousness, doing that which is good and acceptable in his sight, not angsting over the weight of our sins nor measuring the merit of our  good works.  Our overbearing load of debt is paid... The righteousness required before God is secured... By Christ alone!

We remain and always will remain the recipients of a fully gracious, God-initiated sanctification and salvation (Eph. 2:8-10)!