Theophylact of Ohrid, on Heb 13:2

“And hospitality do not forget; for by this some, being not aware of it, have entertained angels.”

“And hospitality, he says, "do not forget." For having suffered the plundering of their possessions, they were perhaps behaving stingily. Or he is also safeguarding them for the future. So important is hospitality, the reception of all people in general, and the non-judgment of brethren, that Abraham and Lot were given the occasion to receive angels (Gen. 18–19). "Without knowing," that is, they did not know that the strangers were angels, yet they received them with honor. This is what makes them great, for if they had known, then in that case they would not have done anything great.”

Imported from an open dataset — not yet checked against the printed edition.