God said to Avraham, "As for you, you will keep my covenant, you and your seed after you throughout their generations.
This is my covenant, which you shall keep, between me and you and your seed after you. Every male among you shall be circumcised.
You shall be circumcised in the flesh of your foreskin. It will be a token of a covenant between me and you.
He who is eight days old will be circumcised among you, every male throughout your generations, he who is born in the house, or bought with money of any foreigner who is not of your seed.
He who is born in your house, and he who is bought with your money, must be circumcised. My covenant will be in your flesh for an everlasting covenant.
The uncircumcised male who is not circumcised in the flesh of his foreskin, that soul shall be cut off from his people. He has broken my covenant."
God said to Avraham, "As for Sarai your wife, you shall not call her name Sarai, but her name will be Sarah.
I will bless her, and moreover I will give you a son by her. Yes, I will bless her, and she will be a mother of nations. Kings of peoples will come from her."
Then Avraham fell on his face, and laughed, and said in his heart, "Will a child be born to him who is one hundred years old? Will Sarah, who is ninety years old, give birth?"
Avraham said to God, "Oh that Yishma'el might live before you!"
God said, "No, but Sarah, your wife, will bear you a son. You shall call his name Yitzchak. I will establish my covenant with him for an everlasting covenant for his seed after him.