The Blessed One gathered all the future souls for every generation at Sinai, and had them all hear all the details of the Oral Law in the glory of His voice, as well as all the restrictions necessary for and worthy of each and every generation. Each and every one received and absorbed it; all its details and its entirety are contained within them. And so, when anyone reaches this world, what the soul received is renewed – its own portion of the Torah. Even if it appears to an individual that by studying it they understand, that is not the case; for that very same thing was lost to them, and they discovers it by effort, but it is always what they received at Sinai.