Genesis 26:35

“Which were a grief of mind unto Isaac, and to Rebekah.] The marriage of them itself was a trouble to them, it being contrary to their will that any of their children should marry with the Canaanites, and those the worst sort of them, the Hittites; it having been the care of Abraham, the father of Isaac, that his son should not marry with them, and laid a strict injunction on his servant not to take a wife for his son from among them; and which was an example to be followed in later times, and which Esau very likely was not ignorant of: and besides this, the women themselves he took for wives were very disagreeable on all accounts, partly because of their religion, being idolaters, and partly…”