Ambrosiaster, on Rom 5:13

“For until the law sin was in the world; but sin was not imputed, when the law was not.”

“Before the law was given, men thought that they could sin with impunity before God but not before other men. For the natural law, of which they were well aware, had not completely lost its force, so that they knew not to do to others what they did not want to suffer themselves. For sin was certainly not unknown among men at that time.How is it then that sin was not imputed, when there was no law? Was it all right to sin, if the law was absent? There had always been a natural law, and it was not unknown, but at that time it was thought to be the only law, and it did not make men guilty before God. For it was not then known that God would judge the human race, and for that reason sin was not imputed, almost as if it did not exist in God's sight and that God did not care about it. But when the law was given through Moses, it became clear that God did care about human affairs and that in the future wrongdoers would not escape without punishment, as they had done up to then.”

Imported from an open dataset — not yet checked against the printed edition.