Genesis 17:17-19 (New International Version)

 ¹⁷ Abraham fell facedown; he laughed and said to himself, "Will a son be born to a man a hundred years old? Will Sarah bear a child at the age of ninety?" ¹⁸ And Abraham said to God, "If only Ishmael might live under your blessing!"

 ¹⁹ Then God said, "Yes, but your wife Sarah will bear you a son, and you will call him Isaac. ^[a] I will establish my covenant with him as an everlasting covenant for his descendants after him.