Genesis 25:22-26 ESV
The children struggled together within her, and she said, “If it is thus, why is this happening to me?” So she went to inquire of the LORD. And the LORD said to her, “Two nations are in your womb, and two peoples from within you shall be divided; the one shall be stronger than the other, the older shall serve the younger.” When her days to give birth were completed, behold, there were twins in her womb. The first came out red, all his body like a hairy cloak, so they called his name Esau. Afterward his brother came out with his hand holding Esau’s heel, so his name was called Jacob. Isaac was sixty years old when she bore them.