Genesis 17:1

The Sign of the Covenant

17:1 When Abram was 99 years old, the Lord appeared to him and said, “I am the sovereign God. Walk before me and be blameless.

Genesis 17:10

17:10 This is my requirement that you and your descendants after you must keep: Every male among you must be circumcised.

Genesis 17:23-27

17:23 Abraham took his son Ishmael and every male in his household (whether born in his house or bought with money) and circumcised them on that very same day, just as God had told him to do. 17:24 Now Abraham was 99 years old when he was circumcised; 17:25 his son Ishmael was thirteen years old when he was circumcised. 17:26 Abraham and his son Ishmael were circumcised on the very same day. 17:27 All the men of his household, whether born in his household or bought with money from a foreigner, were circumcised with him.