Genesis 17:24

22When he finished talking with him, God went up from Abraham.

23Abraham took Ishmael his son, all who were born in his house, and all who were bought with his money: every male among the men of Abraham’s house, and circumcised the flesh of their foreskin in the same day, as God had said to him.

24Abraham was ninety-nine years old when he was circumcised in the flesh of his foreskin.

25Ishmael, his son, was thirteen years old when he was circumcised in the flesh of his foreskin.

26In the same day both Abraham and Ishmael, his son, were circumcised.