Patristic Wisdom: Looking to the Thirteenth Sunday after Pentecost

Then Jesus said to them, “Most assuredly, I say to you, unless you eat the flesh of the Son of Man and drink His blood, you have no life in you. Whoever eats My flesh and drinks My blood has eternal life, and I will raise him up at the last day. For My flesh is food indeed, and My blood is drink indeed. He who eats My flesh and drinks My blood abides in Me, and I in him. As the living Father sent Me, and I live because of the Father, so he who feeds on Me will live because of Me. This is the bread which came down from heaven—not as your fathers ate the manna, and are dead. He who eats this bread will live forever.” (John 6:53–58)

Long-suffering truly and of great mercy is Christ, as one may see from the words now before us. For in no wise reproaching the littleness of soul of the unbelievers, He again richly gives them the life-giving knowledge of the Mystery, and having overcome, as God, the arrogance of those who grieve Him, He tells them those things whereby they shall mount up to endless life. And how He will give them His Flesh to eat, He does not yet tell them, for He knew that they were in darkness, and could never avail to understand the ineffable: but how great good will result from the eating He shows to their profit, that perhaps inciting them to a desire of living in greater preparation for unfading pleasures, He may teach them faith. For to them that have now believed there follows suitably the power too of learning. For so says the prophet Isaiah, If you will not believe neither yet shall you understand. It was therefore right, that faith having been first rooted in them, there should next be brought in understanding of those things whereof they are ignorant, and that the investigation should not precede faith.… For this cause did the Lord with reason refrain from telling them how He would give them His Flesh to eat, and calls them to the duty of believing before seeking. For to those who had at length believed He broke bread, and gave to them, saying, Take, eat, This is My Body. Likewise handing round the Cup to them all, He says, Drink of it all of you, for this is My Blood of the New Testament, which is being shed for many for the remission of sins. Do you see how to those who were yet senseless and thrust from them faith without investigation, He does not explain the mode of the Mystery, but to those who had now believed, He is found to declare it most clearly? Let them then, who of their folly have not yet admitted the faith in Christ, hear, Except you eat the Flesh of the Son of Man and drink His Blood, you have no life in you.

Cyril of Alexandria, Commentary on the Gospel According to St. John 4.2