REASONS WHY IT IS PERFORMED ON THE EIGHTH DAY: Hashem commanded us to circumcise our sons soon after they are born before their intellects develop significantly so that pain will be only physical and therefore minimal. Moreover, once the child grows up, he may refuse to perform it. In addition, it is performed before the parents develop a love for the infant so that it will not be difficult for them either (Moreh Nevuchim ibid.). Hashem said to do so on the eighth day so that the child will be strong enough to undergo the procedure healthily (Devarim Rabbah 6:1). This is because the body’s clotting agents need a week to develop; in fact, they reach their lifetime peak of 110% their normal function on precisely the eighth day (Otzar HaYahadut Vol. 1 p. 405). According to the aforementioned Midrash that compares circumcision to an offering, it can only be performed from the eighth day onward in the same way an animal may only be offered from that time (Rabbeinu Bachayei ibid.). Circumcision is performed on the eighth day because it elevates the Jew beyond the limits of the natural world that was created in seven days (Shem MiShmuel, Zos Chanukah 5681). [This summary was formed based on commentaries culled in Alaktah Ba’Amarim (Bris Milah), by Rabbi Ori Ben-Dov, with the author’s permission.]
