Genesis 25:20-26

and Isaac was forty years old when he married Rebekah daughter of Bethuel the Aramean from Paddan Aram and sister of Laban the Aramean. Isaac prayed to the LORD on behalf of his wife, because she was childless. The LORD answered his prayer, and his wife Rebekah became pregnant. The babies jostled each other within her, and she said, “Why is this happening to me?” So she went to inquire of the LORD. The LORD said to her, “Two nations are in your womb, and two peoples from within you will be separated; one people will be stronger than the other, and the older will serve the younger.” When the time came for her to give birth, there were twin boys in her womb. The first to come out was red, and his whole body was like a hairy garment; so they named him Esau. After this, his brother came out, with his hand grasping Esau’s heel; so he was named Jacob. Isaac was sixty years old when Rebekah gave birth to them.