Genesis 17:21-23

Amplified Bible

²¹ But My covenant [My promise, My solemn pledge], I will establish with Isaac, whom Sarah will bear to you at this time next year.” ²² And God finished speaking with him and went up from Abraham.

²³ Then Abraham took Ishmael his son, and all the servants who were born in his house and all who were purchased with his money, every male among the men of Abraham’s household, and circumcised the flesh of their foreskin the very same day, as God had said to him.