Genesis 17:15-17

17:15 Then God said to Abraham, “As for your wife, you must no longer call her Sarai; Sarah will be her name. 17:16 I will bless her and will give you a son through her. I will bless her and she will become a mother of nations. Kings of countries will come from her!”

17:17 Then Abraham bowed down with his face to the ground and laughed as he said to himself, “Can a son be born to a man who is a hundred years old? Can Sarah bear a child at the age of ninety?”