For I was alive apart from the law once: but when the commandment came, sin revived, and I died.
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Diodorus of Tarsus
If sin “revived” it is clear that it must have been alive at some earlier point and then died. When was that? It was when the devil deceived and defeated Adam, who had received the commandment and knew what transgression meant. Cain too knew that he was sinning, having been commanded not to murder his brother. It was after that that there was no commandment and no law, and so sin was knocked out by the ignorance of those who committed it. .