St. Leo the Great: "The reality of Christ's Body and Blood"

“FOR when the Lord says, ‘unless you have eaten the flesh of the Son of Man, and drunk His blood, you will not have life in you’ (Jn. 6:54), you ought to be partakers at the Holy Table, as to have no doubt whatever concerning the reality of Christ’s Body and Blood. For that is taken in the mouth which is believed in Faith, and it is in vain for them to respond Amen who dispute that which is taken.”

~St. Leo the Great: Sermons, 91:3.

The Institution of the Eucharist, by Nicolas Poussin.

Oil on canvas, 1640; Musée du Louvre, Paris.