Reference for Shevuot 35:3

הדר אמר רבא לעולם בסמוך לוסתה ובתלמיד חכם ותלמיד חכם לזו ואין תלמיד חכם לזו

and in withdrawing he acted wilfully!<span class="x" onmousemove="('comment',' Being learned, and knowing that it is prohibited to withdraw immediately, he is liable to kareth.');">⁴</span> And if an illiterate man, he is liable to bring one, for withdrawing?<span class="x" onmousemove="('comment',' Thinking it is permitted to withdraw immediately, he acted unwittingly.');">⁵</span> Afterwards, Raba said: It really refers to the time near her period, and to a learned man; but a learned man for this,<span class="x" onmousemove="('comment',' Knowing that he ought not to cohabit near the time of her period, yet thinking he still had time before she became unclean; he therefore committed a sin unwittingly (not accidentally, as would be the case if he cohabited not near her period) , and brings a sin offering.');">⁶</span>

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