On the Spirit and the Letter

“But,” say they, “we do praise God as the Author of our righteousness, in that He gave the law, by the teaching of which we have learned how we ought to live.” But they give no heed to what they read: “By the law there shall no flesh be justified in the sight of God.” This may indeed be possible before men, but not before Him who looks into our very heart and inmost will, where He sees that, although the man who fears the law keeps a certain precept, he would nevertheless rather do another thing if he were permitted. And lest any one should suppose that, in the passage just quoted from him, the apostle had meant to say that none are justified by that law, which contains many precepts, under the figure of the ancient sacraments, and among them that circumcision of the flesh itself, which infants were commanded to receive on the eighth day after birth; he immediately adds what law he meant, and says, “For by the law is the knowledge of sin.” He refers then to that law of which he afterwards declares, “I had not known sin but by the law; for I had not known lust except the law had said, You shall not covet.” For what means this but that “by the law comes the knowledge of sin?”