Anti-pelagian Writings by St. Augustine
Chapter 43 [XXVI.]--A Question Touching the Passage in the Apostle About the Gentiles Who are Said to Do by Nature the Law's Commands, Which They are Also Said to Have Written on Their Hearts.
Now we must see in what sense it is that the apostle says, |For when the Gentiles, which have not the law, do by nature the things contained in the law, these, having not the law, are a law unto themselves, which show the work of the law written in their hearts,| lest there should seem to be no certain difference in the new testament, in that the Lord promised that He would write His laws in the hearts of His people, inasmuch as the Gentiles have this done for them naturally. This question therefore has to be sifted, arising as it does as one of no inconsiderable importance. For some one may say, |If God distinguishes the new testament from the old by this circumstance, that in the old He wrote His law on tables, but in the new He wrote them on men's hearts, by what are the faithful of the new testament discriminated from the Gentiles, which have the work of the law written on their hearts, whereby they do by nature the things of the law, as if, forsooth, they were better than the ancient people, which received the law on tables, and before the new people, which has that conferred on it by the new testament which nature has already bestowed on them?|