Genesis 17:21 KJV
But my covenant will I establish with Isaac, which Sarah shall bear unto thee at this set time in the next year.
Genesis 17:21, King James Version
In 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.