Pseudo-Chrysostom — as excerpted in the Catena Aurea on Mark 2:23-28

“(Vict. Ant. e Cat. in Marc.) But our Lord brings forward David, to whom it once happened to eat though it was forbidden by the law, when he touched the Priest’s food, that by his example, he might do away with their accusation of the disciples. For there follows, Have ye never read, &c.”