Although Christ fulfilled the Law for us, so as it is imputed to us, and we made the righteousness of God in him, 2 Cor. 5.21. Yet it doth not follow that we should be freed altogether from the obligation of the Law unto obedience; for the righteousness of Jesus Christ, his obeying and fulfilling of the Law for us, was as the condition of Life, or that upon which the Lord hath promised Justification unto Life; but we may be (and are) obliged to obedience, not for that, but for other ends; not in the least for our Justification and title to Life; but as a part of our Sanctification; and we sin in not obeying, that we may glorifie God by those fruits of our being Spiritually alive. Christ’s obedience was for one end, ours is for another; as his sufferings were for one end, our afflictions for another, and neither of them unnecessary.
Petto: Our Works do not Contribute to Justification