Genesis 17:23-26

23On that same day, Abraham circumcised Ishmael and every male person in his house. He circumcised every male servant that was born in his house, as well as those that he had bought with money. He did this in the way that God had told him.

24Abraham himself was circumcised when he was 99 years old.

25His son, Ishmael, was 13 years old when he was circumcised.

26Abraham and Ishmael were circumcised on the same day.