Genesis 17:19-22

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.