John Chrysostom — as excerpted in the Catena Aurea on Mark 14:22-25

“(ubi sup.) Let there not be therefore a Judas at the table of the Lord; this sacrifice is spiritual food, for as bodily food, working on a belly filled with humours which are opposed to it, is hurtful, so this spiritual food if taken by one polluted with wickedness, rather brings him to perdition, not by its own nature, but through the fault of the recipient. Let therefore our mind be pure in all things, and our thought pure, for that sacrifice is pure. There follows: And he said unto them, This is my blood of the New Testament, which is shed for many.”