Reference for Bekhorot 68:19

אי אמרת יטהר תנן מקמייתא טהר ליה לבתרייתא נטרין ליה ז' ימי משתה

The Rabbis therefore punished him for this very cut.<span class="x" onmousemove="('comment',' Regarding him as if he had never cut off the bahereth at all, so that even if he becomes clean from the second plague, he is not clean from the first, unless the latter plague covers all his flesh.');">⁸</span>

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