“On that very day, Abraham was circumcised, and Ishmael his son” (Genesis 17:26). “On that very day, Abraham was circumcised” – Rabbi Berekhya said: [God said:] “From the beginning, I did not speak in secret” (Isaiah 48:16). The Holy One blessed be He said: Had Abraham circumcised himself at night, all the people of his generation would have said: ‘We declare, had we seen him, we would have not allowed him to circumcise himself.’
However, it was “on that very day, [Abraham was circumcised]”34In broad daylight. – if someone is bothered by it, let him speak up. “Abraham was circumcised” – Rabbi Abba bar Kahana said: He ached and suffered pain, so that the Holy One blessed be He could double his reward.35This is expounded from the fact that the Torah uses a reflexive verb, emphasizing the effect on Abraham. Rabbi Levi said: “Abraham circumcised himself” is not written here, but rather, “was circumcised.”
He examined himself and discovered that he was [miraculously] circumcised.36He felt nothing at all during his circumcision. At that moment, Rabbi Abba bar Kahana disparaged Rabbi Levi. He said to him: ‘You are a fabricator and a falsifier. It is, rather, that he ached and suffered pain, so that the Holy One blessed be He could double his reward.’