God said, “No, but your wife Sarah shall bear you a son, and you shall name him Isaac. I will establish my covenant with him as an everlasting covenant for his offspring after him.
Then one said, “I will surely return to you in due season, and your wife Sarah shall have a son.” And Sarah was listening at the tent entrance behind him.
Then he gave him the covenant of circumcision. And so Abraham became the father of Isaac and circumcised him on the eighth day; and Isaac became the father of Jacob, and Jacob of the twelve patriarchs.
By faith he received power of procreation, even though he was too old—and Sarah herself was barren—because he considered him faithful who had promised.