Genesis 17:23-26

23Then Abraham took Ishmael his son and all of his house-born slaves and all his purchased slaves—every male among the men of Abraham’s house—and he circumcised the flesh of their foreskin on this very same day, just as God had spoken with him.

24Abraham was 99 years old when he was circumcised in the flesh of his foreskin,

25and his son Ishmael was 13 years old when he was circumcised in the flesh of his foreskin.

26On this very same day Abraham and Ishmael his son were circumcised.