If men had been able to keep the natural law which God the Creator planted in the breast of each one, there would have been no need of that law which, written on stone tablets, enmeshed and entangled the weakness of human nature rather than freed and liberated it.
Paul calls the Gentiles Christians because he is the teacher of the Gentiles, as he says elsewhere: “For I speak to you Gentiles.” These people are uncircumcised and do not keep new moons or the sabbath or the law of foods, yet under the guidance of nature they believe in God and in Christ, i.e., in the Father and the Son. To keep the law is to acknowledge the God who gives the law. This is the first part of wisdom: to stand in awe of God the Father, from whom all things come, and the Lord Jesus his Son, through whom all things come. Therefore nature itself acknowledges its Creator by its own judgment, not by the law but by reason, for the creature recognizes its Maker in itself. Commentary on Paul’s Epistles.
"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; uncircumcision observing the precepts of the law".
"For when the Gentiles, which have not the law, do by nature the things of the law, these, having not the law, are a law unto themselves"
When the Gentiles.do by nature, or naturally, that is, without having received any written law, these men are a law to themselves, and have it written in their hearts, as to the existence of a God, and their reason tells them, that many sins are unlawful: they may also do some actions that are morally good, as by giving alms to relieve the poor, honouring their parents not that these actions, morally good, will suffice for their justification of themselves, or make them deserve a supernatural reward in the kingdom of heaven; but God, out of his infinite mercy, will give them some supernatural graces, by which they come to know, and believe, that he will reward their souls for eternity. Such, says St. Chrysostom, were the dispositions of Melchisedech, Job, Cornelius the Centurion (Witham)
When Paul is challenging the pride of Judaism, he is careful not to appear to be condemning the law as such. On the contrary, by extolling the law and showing its greatness he makes good his whole position. When he says “by nature” he means “by the reasoning of nature.” He shows that the Gentiles are on better footing than the Jews. They have not received the law and therefore do not have what seems to give the Jews an advantage over them. For this reason Paul says the Gentiles are to be admired, because they did not need a law, but did all the things which were written in the law, having its works but not its letters engraved on their minds.
"Who that is acquainted with the mystery of God could so significantly relate the law of God, as a man far removed from the knowledge of the truth has set forth that law? But I consider that they who speak true things unconsciously are to be so regarded as though they prophesied
