Genesis 17:19-21

King James Version

¹⁹ And 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.

²⁰ And as for Ishmael, I have heard thee: Behold, I have blessed him, and will make him fruitful, and will multiply him exceedingly; twelve princes shall he beget, and I will make him a great nation.

²¹ But my covenant will I establish with Isaac, which Sarah shall bear unto thee at this set time in the next year.