Genesis 25:22-24

And the children struggled together within her; and she said, If it be so, wherefore do I live? And she went to inquire of Jehovah. And Jehovah said unto her, Two nations are in thy womb, And two peoples shall be separated from thy bowels: And the one people shall be stronger than the other people; And the elder shall serve the younger. And when her days to be delivered were fulfilled, behold, there were twins in her womb.