Genesis 17:19-21

MKJV(i) 19 And God said, Sarah your wife shall bear you a son indeed. And you shall 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 you. Behold, I have blessed him, and will make him fruitful, and will multiply him exceedingly. He shall father twelve chiefs, and I will make him a great nation. 21 But I will establish My covenant with Isaac, whom Sarah shall bear to you at this set time in the next year.