Genesis 17:15-17

God continued speaking to Abraham, “And Sarai your wife: Don’t call her Sarai any longer; call her Sarah. I’ll bless her—yes! I’ll give you a son by her! Oh, how I’ll bless her! Nations will come from her; kings of nations will come from her.” Abraham fell flat on his face. And then he laughed, thinking, “Can a hundred-year-old man father a son? And can Sarah, at ninety years, have a baby?”