Genesis 17:21 in the World English Bible
But I will establish my covenant with Isaac, whom Sarah will bear to you at this set time next year.”
Context
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.
22 And he left off talking with him, and God went up from Abraham.