15
God said to Abraham, "As for Sarai your wife, you shall not call her name Sarai, but her name will be Sarah.
16
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."
17
Then Abraham 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?"
18
Abraham said to God, "Oh that Ishmael might live before you!"
19
God said, "No, but Sarah, your wife, will bear you a son. You shall call his name Isaac. I will establish my covenant with him for an everlasting covenant for his seed after him.