Parshat Toldot, 5th Portion (Genesis 26:30-27:27)
34. And Esau was forty years old, and he married Judith, the daughter of Beeri the Hittite, and Basemath, the daughter of Elon the Hittite.
Rashi
forty years old: Esau was compared to a swine, as it is said (Ps. 80:14): “The boar from the forest gnaws at it.” This swine, when it lies down, stretches out its hooves, as if to say, “See, I am a clean (kosher) animal.” So do these [the chiefs of Esau] rob and plunder and then pretend to be honorable. During the entire forty years, Esau kidnapped wives from their husbands and violated them. When he was forty years old, he said:“My father married at forty; I, too, will do the same.” [From Gen. Rabbah 65:1]