Genesis 17:16-19

16And I will bless her, and give thee a son also by her: yea, I will bless her, and she shall be a mother of nations; kings of people shall come from her.1 17Then Abraham fell upon his face, and laughed, and said in his heart, Shall a child be born to him that is an hundred years old? and shall Sarah, who is ninety years old, bear? 18And Abraham said to God, O that Ishmael might live before thee! 19And God said, Sarah thy wife shall bear thee a son indeed; and thou shalt call his name Isaac: and I will establish my covenant with him for an everlasting covenant, and with his seed after him.