Discussions with Protestants about the Real Presence of Christ in the Eucharist very quickly turn to John 6:30-71, the Bread of Life Discourse. Once there, they will try to establish that Christ speaks only metaphorically, often by comparing related passages such as Luke 22:20. In that text, Jesus says, “This cup is my blood.” See! the Protestant will cry triumphantly. No one says the cup itself is his blood. So obviously it’s all a metaphor. (Here and here are an example of this.)
One way to respond to this is to point out that just because one word (cup) is used metaphorically does not imply that another word (blood) must also be metaphorical. Where would we stop? Taken to its logical conclusion, that would have to mean that the crucifixion and resurrection themselves are metaphors. And no Protestant, at least no orthodox one, would want to go that far. So John 6 needs to be read on its own terms.
And there are, in my view, 3 good reasons to take John 6 literally.
1. The Jews understood Jesus literally, and he did not correct them.
“How can this man give us his flesh to eat?” they ask. You can understand their distress: To eat human flesh, and drink blood, was an abomination (Lev. 17:10). So if Christ was merely using a figure, that was the time for him to reassure the Jews on that point. But he did not. Instead, he repeated himself, and in even stronger terms.
So Jesus said to them, “Truly truly I say to you, unless you eat the flesh of the Son of man and drink his blood you have no life in you; he who eats my flesh and drinks my blood has eternal life, and I will raise him up on the last day. For my flesh is food indeed and my blood is drink indeed.” (John 6:53-55)
In the last verse, Christ specifically denies that he is speaking metaphorically. “This is a hard saying,” the disciples say. “Who can listen to it?” But rather than say, “You have misunderstood,” Christ only acknowledges their offense without correcting the way they have understood him. Many of his followers abandoned him at that point. He let them go; he did not say they had misunderstood.
To his disciples he says, not, Do you also misunderstand? but “Will you also go away?” He gives no indication at all of having been misunderstood literally when He meant His words figuratively. And Peter says, “Lord, to whom shall we go?” Those are words of abandonment to Christ—not of human reason reassured, but of faith despite the limitations of human reason.
2. St. Paul’s strong language about the Eucharist.
In 1 Cor. 11:26-29, St. Paul says:
For as often as you eat this bread and drink the cup, you proclaim the Lord’s death until he comes. Whoever, therefore, eats the bread or drinks the cup of the Lord in an unworthy manner will be guilty of profaning the body and blood of the Lord. Let a man examine himself, and so eat of the bread and drink of the cup. For any one who eats and drinks without discerning the body eats and drinks judgment upon himself.
The language is far too hard and direct if St. Paul merely has a symbol in mind. To eat and drink the Eucharist unworthily means you profane Christ. To eat and drink without discerning the body puts you under judgment. That is not how you talk if this is just a symbol; that is how you talk if this really is the body, blood, soul, and divinity of Jesus Christ.
3. The unanimous witness of the early Church.
And I do mean unanimous.
Justin Martyr: “For not as common bread nor common drink do we receive these; but since Jesus Christ our Savior was made incarnate by the word of God and had both flesh and blood for our salvation, so too, as we have been taught, the food which has been made into the Eucharist by the Eucharistic prayer set down by him, and by the change of which our blood and flesh is nurtured, is both the flesh and the blood of that incarnated Jesus” (First Apology 66, here).
Ignatius of Antioch: “Take note of those who hold heterodox opinions on the grace of Jesus Christ which has come to us, and see how contrary their opinions are to the mind of God. … They abstain from the Eucharist and from prayer because they do not confess that the Eucharist is the flesh of our Savior Jesus Christ, flesh which suffered for our sins and which that Father, in his goodness, raised up again. They who deny the gift of God are perishing in their disputes” (Letter to the Smyrnaeans 6–7, here).
St. Cyril of Alexandria: “The offerings, by the hidden power of God Almighty, are changed into Christ’s Body and Blood” (Commentary on Matthew 26–27, quoted here).
Cyril of Jerusalem: “After the invocation the Bread becomes the Body of Christ, and the Wine the Blood of Christ” (Catechetical Lectures 19:7, here).
Cyril of Jerusalem: Since then He Himself declared and said of the Bread, This is My Body, who shall dare to doubt any longer? And since He has Himself affirmed and said, This is My Blood, who shall ever hesitate, saying, that it is not His blood?” (Catechetical Lectures 22:1, here).
Who shall dare to doubt?