God said to Abraham, "You also must agree to keep the covenant with me, both you and your descendants in future generations.
You and your descendants must all agree to circumcise every male among you. 1
References for Genesis 17:10
17.10 Ac 7.8; Ro 4.11.
From now on you must circumcise every baby boy when he is eight days old, including slaves born in your homes and slaves bought from foreigners. This will show that there is a covenant between you and me.
Each one must be circumcised, and this will be a physical sign to show that my covenant with you is everlasting.
Any male who has not been circumcised will no longer be considered one of my people, because he has not kept the covenant with me."
God said to Abraham, "You must no longer call your wife Sarai; from now on her name is Sarah.
References for Genesis 17:15
I will bless her, and I will give you a son by her. I will bless her, and she will become the mother of nations, and there will be kings among her descendants."
Abraham bowed down with his face touching the ground, but he began to laugh when he thought, "Can a man have a child when he is a hundred years old? Can Sarah have a child at ninety?"
He asked God, "Why not let Ishmael be my heir?"
But God said, "No. Your wife Sarah will bear you a son and you will name him Isaac. I will keep my covenant with him and with his descendants forever. It is an everlasting covenant.
References for Genesis 17:19
I have heard your request about Ishmael, so I will bless him and give him many children and many descendants. He will be the father of twelve princes, and I will make a great nation of his descendants.