Since [Jesus] himself has declared and said of the bread: “This is my body,” who shall dare to doubt any longer? And since he has affirmed and said, “This is my blood,” who shall ever hesitate, saying that it is not his blood? For thus we come to bear Christ in us, because his Body and Blood are diffused through our members; thus it is that, according to the blessed Peter: “we become partakers of the divine nature.”

Contemplate therefore the bread and wine not as bare elements, for they are, according to the Lord’s declaration, the Body and Blood of Christ; though sense suggests this to you, let faith steady you. Judge not the matter from taste, but from faith be fully assured without misgiving, that you have been vouchsafed the Body and Blood of Christ.

—Cyril, Bishop of Jerusalem [late 4th century], Mystagogical Catechesis, 4