Genesis 17:19-21

19But God said, “No, but your wife Sarah will bear you 1a son, and you shall name him 2Isaac; and 3I will establish My covenant with him as an everlasting covenant for his 4descendants after him.

20As for Ishmael, I have heard you; behold, I will bless him, and 5make him fruitful and multiply him exceedingly. 6He shall father twelve princes, and I will make him into a 7great nation.

21But I will establish My covenant with 8Isaac, whom 9Sarah will bear to you at this season next year.”