Jamieson, Fausset and Brown on Genesis 26:34

34. Esau ... took to wife--If the pious feelings of Abraham recoiled from the idea of Isaac forming a matrimonial connection with a Canaanitish woman [Ge 24:3], that devout patriarch himself would be equally opposed to such a union on the part of his children; and we may easily imagine how much his pious heart was wounded, and the family peace destroyed, when his favorite but wayward son brought no less than two idolatrous wives among them--an additional proof that Esau neither desired the blessing nor dreaded the curse of God. These wives never gained the affections of his parents, and this estrangement was overruled by God for keeping the chosen family aloof from the dangers of heathen influence.