Genesis 17:17-24

17Abraham fell down so that his face touched the ground. He laughed and he said to himself, ‘I am now 100 years old. That is too old to have a son. Sarah is 90 years old, so she could never give birth to a child. That is too old to have a child.’

18So Abraham said to God, ‘I would be happy if you would bless Ishmael as my son.’

19God said to Abraham, ‘No, your wife Sarah will give birth to a son for you. You must give him the name “Isaac”. I will make my covenant with him and with his descendants for all time.

20I have heard what you want me to do for Ishmael. I will bless him. I will cause him to have many descendants. Among his descendants there will be 12 rulers. His descendants will become a great nation.

21But I will make my covenant with Isaac, not with Ishmael. At about this time next year, Sarah will give birth to your son, Isaac.’

22When God had finished speaking to Abraham, he went away.

23On that same day, Abraham circumcised Ishmael and every male person in his house. He circumcised every male servant that was born in his house, as well as those that he had bought with money. He did this in the way that God had told him.

24Abraham himself was circumcised when he was 99 years old.