Genesis 17:16-17

I will bless her, and indeed I will also give you a son by her. Yes, I will bless her, and she shall be a mother of nations; kings of peoples will come from her.” Then Abraham fell on his face and laughed, and said in his heart, “Shall a child be born to a man who is a hundred years old? And shall Sarah, who is ninety years old, bear a child?”