Genesis 25:22-24

But the two children struggled with each other in her womb. So she went to ask the LORD about it. “Why is this happening to me?” she asked. And the LORD told her, “The sons in your womb will become two nations. From the very beginning, the two nations will be rivals. One nation will be stronger than the other; and your older son will serve your younger son.” And when the time came to give birth, Rebekah discovered that she did indeed have twins!