Genesis 17:21-23

New Revised Standard Version, Anglicised

²¹ But my covenant I will establish with Isaac, whom Sarah shall bear to you at this season next year.’ ²² And when he had finished talking with him, God went up from Abraham.

²³ Then Abraham took his son Ishmael and all the slaves born in his house or bought with his money, every male among the men of Abraham’s house, and he circumcised the flesh of their foreskins that very day, as God had said to him.