Rashi on Genesis 24:37/רש"י על בראשית כ״ד:ל״ז

1לא תקח אשה לבני מבנות הכנעני THOU SHALT NOT TAKE A WIFE FOR MY SON FROM THE DAUGHTERS OF THE CANAANITES if you do not first go to my father’s house and to my family that thou mayest take a wife to my son and she will not be willing to follow you.