Sforno on Genesis 25:23/ספורנו על בראשית כ״ה:כ״ג

1שני גוים בבטנך, this is the reason for the quarrelling you experience inside your womb.

2ושני לאמים, they will also be politically different from one another, being separate kingdoms.

3ממעיך יפרדו, they will go their different ways after being born, neither of them will die at birth as you fear.