Parashas Toldos · Passuk 26:34
When Esav was forty years old, he took to wife Yehudit daughter of Be’eri the Hittite, and Basemat daughter of Elon the Hittite.
Rashi on Bereishis 26:34 (classical source on this passuk; not listed as a numbered Torah Temimah unit here).
Lemma / focus: בן ארבעים שנה.
English: Esav is compared to a pig… the pig when it lies stretches out its hoofs and says, See that I am pure; so these plunder and rob and present themselves as worthy. For forty years Esav had been seizing women from under their husbands; at forty he said: Father married at forty, so will I.
Derash on the verse (Rashi / midrash) — not a formal named middah of the 13: the age is read against Yitzchak’s marriage age and against Esav’s character.
Esav married at forty in imitation of Yitzchak, yet the midrash compares him to a pig that displays clean hoofs while its nature is otherwise.