Galatians 3:10

Further, they were possessed with another apprehension; it was written, "Cursed is every one that continueth not in all things that are written in the book of the Law, to do them." (Deut. xxvii: 26) And this he removes, with great skill and prudence, turning their argument against themselves, and showing that those who relinquish the Law are not only not cursed, but blessed; and they who keep it, not only not blessed but cursed. They said that he who kept not the Law was cursed, but he proves that he who kept it was cursed, and he who kept it not, blessed. Again, they said that he who adhered to Faith alone was cursed, but he shows that he who adhered to Faith alone, is blessed. And how does he prove all this? for it is no common thing which we have promised; wherefore it is necessary to give close attention to what follows. He had already shown this, by referring to the words spoken to the Patriarch, "In thee shall all nations be blessed," (Gen. xii: 4) at a time, that is, when Faith existed, not the Law; so he adds by way of conclusion, "So then they which be of faith are blessed with the faithful Abraham." Then, that they might not turn round, and object that, true it was Abraham was justified by Faith, for the Law was not then given, but what instance would be found of Faith justifying after the delivery of the Law? he addresses himself to this, and proves more than they required: namely, not only that Faith was justifying, but that the Law brought its adherents under a curse. To be sure of this, listen to the very words of the Apostle. "For as many as are of the works of the Law are under a curse." This is what he lays down, before proving it; and what is the proof? it is from the Law itself...

For all have sinned, and are under the curse. However he does not say this yet, lest he should seem to lay it down of himself, but here again establishes his point by a text which concisely states both points; that no man has fulfilled the Law, (wherefore they are under the curse,) and, that Faith justifies. What then is the text? It is in the book of the prophet Habakkuk, "The just shall live by faith," (Hab. ii: 4) which not only establishes the righteousness that is of Faith, but also that there is no salvation through the Law. As no one, he says, kept the Law, but all were under the curse, on account of transgression, an easy way was provided, that from Faith, which is in itself a strong proof that no man can be justified by the Law. For the prophet says not, "The just shall live by the Law," but, "by faith."