Not "only" Justified, we are Sanctified by grace

Our whole salvation is by the grace of God in Christ alone.  John Calvin's commentary on Ephesians 2:10 -

10. For we are his work. By setting aside the contrary supposition, he proves his statement, that by grace we are saved, -- that we have no remaining works by which we can merit salvation; for all the good works which we possess are the fruit of regeneration. Hence it follows, that works themselves are a part of grace.     

When he says, that "we are the work of God," this does not refer to ordinary creation, by which we are made men. We are declared to be new creatures, because, not by our own power, but by the Spirit of Christ, we have been formed to righteousness. This applies to none but believers. As the descendants of Adam, they were wicked and depraved; but by the grace of Christ, they are spiritually renewed, and become new men. Everything in us, therefore, that is good, is the supernatural gift of God. The context explains his meaning. We are his work, because we have been created, -- not in Adam, but in Christ Jesus, -- not to every kind of life, but to good works.   

What remains now for free-will, if all the good works which proceed from us are acknowledged to have been the gifts of the Spirit of God?  Let godly readers weigh carefully the apostle's words. He does not say that we are assisted by God. He does not say that the will is prepared, and is then left to run by its own strength. He does not say that the power of choosing aright is bestowed upon us, and that we are afterwards left to make our own choice. Such is the idle talk in which those persons who do their utmost to undervalue the grace of God are accustomed to indulge. But the apostle affirms that we are God's work, and that everything good in us is his creation; by which he means that the whole man is formed by his hand to be good. It is not the mere power of choosing aright, or some indescribable kind of preparation, or even assistance, but the right will itself, which is his workmanship; otherwise Paul's argument would have no force. He means to prove that man does not in any way procure salvation for himself, but obtains it as a free gift from God. The proof is, that man is nothing but by divine grace. Whoever, then, makes the very smallest claim for man, apart from the grace of God, allows him, to that extent, ability to procure salvation.     

Created to good works. They err widely from Paul's intention, who torture this passage for the purpose of injuring the righteousness of faith. Ashamed to affirm in plain terms, and aware that they could gain nothing by affirming, that we are not justified by faith, they shelter themselves under this kind of subterfuge. "We are justified by faith, because faith, by which we receive the grace of God, is the   commencement of righteousness; but we are made righteous by regeneration, because, being renewed by the Spirit of God, we walk in good works."  In this manner they make faith the door by which we enter into righteousness, but imagine that we obtain it by our works, or, at least, they define righteousness to be that uprightness by which a man is formed anew to a holy life. I care not how old this error may be; but they err egregiously who endeavor to support it by this passage.     

We must look to Paul's design. He intends to shew that we have brought nothing to God, by which he might be laid under obligations to us; and he shews that even the good works which we perform have come from God.  Hence it follows, that we are nothing, except through the pure exercise of his kindness. Those men, on the other hand, infer that the half of our justification arises from works. But what has this to do with Paul's intention, or with the subject which he handles? It is one thing to inquire in what righteousness consists, and another thing to follow up the doctrine, that it is not from ourselves, by this argument, that we have no right to claim good works as our own, but have been formed by the Spirit of God, through the grace of Christ, to all that is good.  When Paul lays down the cause of justification, he dwells chiefly on this point, that our consciences will never enjoy peace till they rely on the propitiation for sins. Nothing of this sort is even alluded to in the present instance. His whole object is to prove, that,     

"by the grace of God, we are all that we are."   (1 Corinthians 15:10)     

Which God hath prepared...  Beware of applying this, as the Pelagians do, to the instruction of the law; as if Paul's meaning were, that God commands what is just, and lays down a proper rule of life. Instead of this, he follows up the doctrine which he had begun to illustrate, that salvation does not proceed from ourselves. He says, that, before we were born, the good works were prepared by God; meaning, that in our own strength we are not able to lead a holy life, but only so far as we are formed and adapted by the hand of God. Now, if the grace of God came before our performances, all ground of boasting has been taken away. Let us carefully observe the word prepared. On the simple ground of the order of events, Paul rests the proof that, with respect to good works, God owes us nothing. How so? Because they were drawn out of his treasures, in which they had long before been laid up; for whom he called, them he justifies and regenerates.    

Note: I think the word regenerates in the last sentence may best be understood as sanctifies.