Then God said, “No, but your wife Sarah will bear you a son, and you will call his name Isaac. I will establish My covenant with him as an everlasting covenant and with his descendants after him.
One of them said, “I will certainly return to you about this time next year, and Sarah your wife will have a son.” And Sarah heard it in the tent door, which was behind him.
Then He gave him the covenant of circumcision. And Abraham became the father of Isaac and circumcised him on the eighth day. And Isaac became the father of Jacob, and Jacob became the father of the twelve patriarchs.
By faith Sarah herself also received the ability to conceive seed, and she bore a child when she was past the age, because she judged Him faithful who had promised.