Therefore, when we speak of justifying faith, (fide justificante,) it includes first, the divine promises; secondly, that they offer grace freely and without our merit; thirdly, that the blood of Christ and his merits are the treasure which atones for our sins. The promises are received through faith; but as they offer grace without merit, all our worthiness and merit fall to the ground, and grace and boundless mercy alone are praised. The merit of Christ is the treasure; for that must indeed be a treasure and a noble pledge, which pays for the sins of the whole world. All the Scriptures, of the Old and New Testaments, when speaking of God and faith, often use the expressions—goodness, mercy; and in all their writings the holy Fathers teach, that we are saved by grace, goodness, and forgiveness.

Now whenever we find the word mercy in the Scriptures, or in the writings of the Fathers, we must remember, that it refers to faith, which embraces the promise of such mercy.

Again, whenever the Scriptures speak of faith, they mean the faith which is based upon grace alone. For faith does not justify us before God, as though it were in itself our work, and our own, but solely because it receives the grace; promised and offered without merit and presented out of the rich treasures of mercy. (Henkel Translation, p. 167).

From this it is easy to perceive the difference between faith, and the piety produced by the law. For faith is a divine worship and service, (latria,) in which we are the recipients of gifts; but the righteousness of the law is a worship which offers our works to God. Accordingly, God requires us to worship him through faith, that we may receive from him what he promises and offers. Faith, however, is not a mere historical knowledge, but a conviction which firmly cleaves to the divine promises, as Paul fully shows, when he says, Rom. 4:16: “Therefore it is of faith, that it might be by grace; to the end of the promise might be sure to all the seed.” Here Paul so connects the two, that faith, &c., must follow promises; and again, reciprocally, where promises are given, God also requires faith.

But we can show even more plainly, what justifying faith is, by referring to our own Creed and Faith; for the Symbol says: I believe in the remission of sin. Hence it is not enough for us to know or believe that Christ was born, that he suffered and rose from the dead, but we must also believe the article which sets forth the final object of all this, namely, “I believe that my sins are forgiven me.” To this article all the rest must be referred, namely, that our sins are forgiven for Christ’s sake, and not on account of our merit. For why should God give Christ for our sins, if our merit could atone for them?  (Henkel Translation, p. 166-167).

What the faith is, which justifies us before God.

Our adversaries think, that faith consists in a knowledge of, or an acquaintance with, the history of Christ; hence they teach that we can believe, even when sunk in moral sin. Accordingly they neither know nor say anything of the true Christian faith, by which, Paul invariably says, we are justified before God. For those that are just and holy in the sight of God, are surely not in mortal sin. Therefore the faith, which justifies us before God, consists not only in a knowledge of the history of Christ, his birth, sufferings, &c., (for this even the devils have,) but it is the conviction, the fixed, firm confidence of our hearts, fully trusting in the promises of God, which, without our merit, offer us the remission of sin, grace, and full salvation, through Christ the Mediator. And that no one may suppose it to be a mere historical knowledge, I add that faith is the acceptance of this treasure with our whole heart, and this is not our own act, present or gift, our own work or preparation; but the heart must be assured and fully trust, that God presents and gives to us, and not we to him; that he pours out upon us the whole treasure of grace in Christ. (Henkel Translation, p. 166).