Sforno on Genesis 26:34/ספורנו על בראשית כ״ו:ל״ד

1ויהי עשו בן ארבעים שנה, at that point Yitzchok was 100 years old and he did not bother to see to it that both of his sons should be provided with suitable wives. As a result,

2ויקח אשה, את יהודית בת בארי החתי, apparently Yitzchok did not object to his sons marrying Canaanite girls, something his father had objected to strenuously.