Holy Eucharist Teachings by the Fathers of the Church
"Since Christ Himself said in reference to the bread: "This is My Body," who will dare remain hesitant? And since with equal clarity He asserted: "This is My Blood," who will dare entertain any doubt and say that this is not His Blood?... You have been taught these truths. Imbued with the certainty of faith, you know that what seems to be bread is not bread but the Body of Christ, although it seems to be bread when tasted. You also know that what seems to be wine is not wine but the Blood of Christ although it does taste like wine."
Holy Eucharist teachings by the Fathers of the Church - Cyril of Jerusalem