Parashas Vayeira · Passuk 18:8
He took curds and milk and the calf that he had prepared, and set them before them; and he stood over them under the tree, and they ate.
Torah Temimah points to Bava Metzia 86b.
TT lemma: ויאכלו.
English: “And they ate.” Rabbi Tanchum bar Chanilai said: A person should never deviate from local custom, for Moshe ascended on high and did not eat bread, while the ministering angels descended below and ate bread, as it is written, “And they ate.”
Derash on the verse (Bavli sugya) — not a formal named middah of the 13. The angels’ behavior on earth is contrasted with Moshe’s behavior in heaven to establish a general rule of etiquette.
One should follow the custom of the place: the angels ate when they visited earth, just as Moshe refrained from eating when he ascended to heaven.