Genesis 17:25
Ishmael, his son, was thirteen years old when he was circumcised in the flesh of his foreskin.
World English Bible (Public Domain)
In context
Before · Genesis 17:23–24
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.