Genesis 17:23-25

Darby Translation

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

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

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