Now, that faith signifies, not only a knowledge of the history, but such faith as assents to the promise, Paul plainly testifies when he says, Rom. 4, 16: Therefore it is of faith, to the end the promise might be sure. For he judges that the promise cannot be received unless by faith. Wherefore he puts them together as things that belong to one another, and connects promise and faith. [There Paul fastens and binds together these two, thus: Wherever there is a promise faith is required and conversely, wherever faith is required there must be a promise.] Although it will be easy to decide what faith is if we consider the Creed where this article certainly stands: The forgiveness of sins. Therefore it is not enough to believe that Christ was born, suffered, was raised again, unless we add also this article, which is the purpose of the history: The forgiveness of sins. To this article the rest must be referred, namely, that for Christ's sake, and not for the sake of our merits, forgiveness of sins is given us. For what need was there that Christ was given for our sins if for our sins our merits can make satisfaction? As often, therefore, as we speak of justifying faith, we must keep in mind that these three objects concur: the promise, and that, too, gratuitous, and the merits of Christ, as the price and propitiation. The promise is received by faith; the "gratuitous" excludes our merits, and signifies that the benefit is offered only through mercy; the merits of Christ are the price, because there must be a certain propitiation for our sins. Scripture frequently implores mercy, and the holy Fathers often say that we are saved by mercy. As often, therefore, as mention is made of mercy, we must keep in mind that faith is there required, which receives the promise of mercy. And, again, as often as we speak of faith, we wish an object to be understood, namely, the promised mercy. For faith justifies and saves, not on the ground that it is a work in itself worthy, but only because it receives the promised mercy.