Genesis 17:18-23

18And Abraham said to God, “If only Ishmael might live under your blessing!” 19Then God said, “Yes, but your wife Sarah will bear you a son, and you will call him Isaac. Isaac means he laughs. I will establish my covenant with him as an everlasting covenant for his descendants after him. 20And as for Ishmael, I have heard you: I will surely bless him; I will make him fruitful and will greatly increase his numbers. He will be the father of twelve rulers, and I will make him into a great nation. 21But my covenant I will establish with Isaac, whom Sarah will bear to you by this time next year.”

22When he had finished speaking with Abraham, God went up from him. 23On that very day Abraham took his son Ishmael and all those born in his household or bought with his money, every male in his household, and circumcised them, as God told him.