For as many as have sinned without law shall also perish without law: and as many as have sinned in the law shall be judged by the law;
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How can someone sin without the law, when Paul says that everyone is subject to the law of nature? By “law” he means the law of Moses, to which the Jews are bound although they do not believe. The Gentiles are also under the judgment of the natural law, but only insofar as they have chosen not to attach themselves to it. Thus the Gentile unbelievers are doubly in trouble, because they have neither assented to the law given through Moses, nor have they received the grace of Christ. Therefore it is quite right that they should perish. So just as the person who sins without the law will perish, so also the one who has kept the law without knowing it will be justified. For the keeper of the law maintains his righteousness by nature. For if the law is given not for the righteous but for the unrighteous, whoever does not sin is a friend of the law. For him faith alone is the way by which he is made perfect. For others mere avoidance of evil will not gain them any advantage with God unless th...
The apostle did not mean to say that those who sin in ignorance will suffer worse punishment than those who know the law. It seems that it is worse to perish than to be judged. Rather the apostle here was merely distinguishing between Jews and Gentiles.
Whosoever have sinned without the law. That is, without the written law of Moses, against their reason and conscience And also those who being Jews, have sinned under this written law, shall be judged, even with greater severity, for having transgressed against the known law. (Witham)
Paul says that the Jews have a much greater need of grace than the Gentiles. Because the Jews said that they were justified by the law and therefore did not need grace, Paul shows that they need it even more than the Gentiles, given that they are liable to be punished more severely.
If, then, God will judge the secrets of men-both of those who have sinned in the law, and of those who have sinned without law (inasmuch as they who know not the law yet do by nature the things contained in the law)