We believe that this true faith, produced in us by the hearing of God’s Word and by the work of the Holy Spirit, regenerates us and makes us new creatures [2 Cor 5:17], causing us to live a new life [Rom 6:4] and freeing us from the slavery of sin.
Therefore, far from making people cold toward living in a pious and holy way, this justifying faith, quite to the contrary, so works within them that apart from it they will never do a thing out of love for God but only out of love for themselves and fear of being condemned.
So then, it is impossible for this holy faith to be unfruitful in a human being, seeing that we do not speak of an empty faith but of what Scripture calls “faith working through love” [Gal 5:6], which moves people to do by themselves the works that God has commanded in the Word.
These works, proceeding from the good root of faith, are good and acceptable to God, since they are all sanctified by God’s grace. Yet they do not count toward our justification—for by faith in Christ we are justified, even before we do good works. Otherwise they could not be good, any more than the fruit of a tree could be good if the tree is not good in the first place.
So then, we do good works, but not for merit—for what would we merit? Rather, we are indebted to God for the good works we do, and not God to us, since God “is at work in us, enabling us both to will and to work for his good pleasure” [Phil 2:13]—thus keeping in mind what is written: “When you have done all that you were ordered to do, say, ‘We are worthless slaves; we have done only what we ought to have done'” [Luke 17:10].
Yet we do not wish to deny that God rewards good works—but it is by grace that God crowns these gifts.
Moreover, although we do good works we do not base our salvation on them; for we cannot do any work that is not defiled by our flesh and also worthy of punishment. And even if we could point to one, memory of a single sin is enough for God to reject that work.
So we would always be in doubt, tossed back and forth without any certainty, and our poor consciences would be tormented constantly if they did not rest on the merit of the suffering and death of our Savior.