Genesis 17:15–21

15 God said also to Abraham: Sarai thy wife thou shalt not call Sarai, but Sara.

16 And I will bless her, and of her I will give thee a son, whom I will bless, and he shall become nations, and kings of people shall spring from him.

17 Abraham fell upon his face, and laughed, saying in his heart: Shall a son, thinkest thou, be born to him that is a hundred years old? and shall Sara that is ninety years old bring forth?

18 And he said to God: O that Ismael may live before thee.

19 And God said to Abraham: Sara thy wife shall bear thee a son, and thou shalt call his name Isaac, and I will establish my covenant with him for a perpetual covenant, and with his seed after him.

20 And as for Ismael I have also heard thee. Behold, I will bless him, and increase, and multiply him exceedingly: he shall beget twelve chiefs, and I will make him a great nation.

21 But my covenant I will establish with Isaac, whom Sara shall bring forth to thee at this time in the next year.