“You shall surely circumcise those born in your house, or those purchased with your silver, and My covenant shall be in your flesh for an eternal covenant” (Genesis 17:13). “You shall surely circumcise [himol yimol]” – this43The double expression himol yimol. refers to circumcision and the uncovering,44Uncovering the head of the corona by peeling back the membrane under the foreskin. [moreover,] it refers to circumcision and removal of the shreds.45Shreds of skin that may remain after the circumcision. [Moreover,] himol yimol – from here we learn that the circumciser must himself be circumcised. [Moreover,] himol yimol – this is to include one who was born circumcised.46Although he obviously cannot undergo circumcision, he must have a drop of blood drawn from the place where the foreskin would have been.
This is called covenantal blood. It is taught: Rabbi Shimon ben Elazar says: Beit Shammai and Beit Hillel did not dispute that one must draw covenantal blood from one who is born circumcised, because it is a compressed foreskin.47Although it is not visible as a separate piece of flesh, there is an undeveloped foreskin compressed to the skin. Regarding what do they disagree? Regarding a proselyte who converted when [already] circumcised, as Beit Shammai say: One must draw covenantal blood from him and Beit Hillel say: One need not do so.
Rabbi Eliezer son of Rabbi Yosei HaGelili says: Beit Shammai and Beit Hillel did not disagree, neither regarding this case nor regarding that case, [but agree] that one must draw the covenantal blood. Regarding what do they disagree? Regarding one who was born circumcised, when his eighth day coincides with Shabbat, as Beit Shammai say: One must draw the covenantal blood from him,48Even though this would involve Shabbat desecration. and Beit Hillel say: One need not do so.49That is, it is forbidden to desecrate Shabbat for such drawing of blood, and it should be postponed to the following day.
Rabbi Yitzḥak said in the name of Rabbi Hoshaya: The halakha is in accordance with the statement of the disciple.50Rabbi Shimon ben Elazar.