2:20,21 Here, in his own person, the apostle describes the spiritual or hidden life of a believer. The old man is crucified, Ro 6:6, but the new man is living; sin is mortified, and grace is quickened. He has the comforts and the triumphs of grace; yet that grace is not from himself, but from another. Believers see themselves living in a state of dependence on Christ. Hence it is, that though he lives in the flesh, yet he does not live after the flesh. Those who have true faith, live by that faith; and faith fastens upon Christ's giving himself for us. He loved me, and gave himself for me. As if the apostle said, The Lord saw me fleeing from him more and more. Such wickedness, error, and ignorance were in my will and understanding, that it was not possible for me to be ransomed by any other means than by such a price. Consider well this price. Here notice the false faith of many. And their profession is accordingly; they have the form of godliness without the power of it. They think they believe the articles of faith aright, but they are deceived. For to believe in Christ crucified, is not only to believe that he was crucified, but also to believe that I am crucified with him. And this is to know Christ crucified. Hence we learn what is the nature of grace. God's grace cannot stand with man's merit. Grace is no grace unless it is freely given every way. The more simply the believer relies on Christ for every thing, the more devotedly does he walk before Him in all his ordinances and commandments. Christ lives and reigns in him, and he lives here on earth by faith in the Son of God, which works by love, causes obedience, and changes into his holy image. Thus he neither abuses the grace of God, nor makes it in vain.
21. I do not frustrate the grace of God—I do not make it void, as thou, Peter, art doing by Judaizing.
for—justifying the strong expression "frustrate," or "make void."
is dead in vain—Greek, "Christ died needlessly," or "without just cause." Christ's having died, shows that the law has no power to justify us; for if the law can justify or make us righteous, the death of Christ is superfluous [Chrysostom].