Genesis 26:35

and I will make you swear by Yahweh, the God of heaven and the God of earth, that you shall not take a wife for my son from the daughters of the Canaanites, among whom I live,

Then Rebekah said to Isaac, “I am tired of living because of the daughters of Heth; if Jacob takes a wife from the daughters of Heth, like these, from the daughters of the land, what good will my life be to me?”

So Esau saw that the daughters of Canaan were displeasing in the sight of his father Isaac;

that also there be no sexually immoral or godless person like Esau, who sold his own birthright for a single meal.