Exegesis of John 6, "Bread of Life Discourse"
Note: All scriptural chapter and verse citations without a name will be for John's Gospel. All other scriptural citations will include the book name. All scriptural quotations are from the Revised Standard Version-Catholic Edition
After he first after broke with the Catholic Church, Martin Luther still held to the Catholic teaching of John 6. Luther continued to teach that Jesus, in the extended "Bread of Life" discourse, was being utterly literal in equating his own salvific body and blood with the Eucharist later instituted at the Last Supper. Sometime later in his career, Luther changed his mind, and seeing the discourse (especially the later part, verses 61-65) dealt with the necessity of faith, declared the discourse was really about salvific faith in Christ quite apart from any sacramental usage. Luther continued to teach the Real Presence of Christ in the Eucharist (Lutheran "co-substantiation"), holding Jesus' declarations at the Last Supper and Paul's Eucharistic commentaries more than proved the doctrine.
It is possible Luther's re-interpretation was motivated from the otherwise scarcity of any of Christ's words supporting the Lutheran doctrine of "salvation by faith alone" (sola fide). Luther (practically snarling as he did so) admitted he added the word "alone" in his German translation of Romans 5:1 where the Koine Greek did not have it (and really does not imply it). Luther knew his position was also vulnerable in his rejection of several New Testament books as canonical because they contradicted his "gospel of salvation" thesis. Luther's quite public elimination of contrary evidence was cited by contemporary Catholic apologists challenging Luther's intellectual and scholarly integrity.
In over-emphasizing one point of John 6 and ignoring the qualifying remainder, Luther was sure Christ was preaching salvation by faith alone. For Luther, if Christ himself preached sola fide, "That was that".
There is no historical evidence that reformers, such as Calvin and Zwingli, used Luther’s exegesis. But utterly deny the Real Presence Ulrich Zwingli and his followers did, to Luther's anguish and anger.
When they are not ignoring John 6, contemporary deniers of the Real Presence follow Luther's lead. This includes Luther's tactic of rejecting contrary evidence within the discourse itself. Skipping over several verses of John 6 is practically mandatory to support the denial of the Real Presence. A Catholic apologist must intimately learn John 6, to point out all verses an objector ignores, uses out of context, or just misunderstands.
Let's begin with two events right before Jesus' Bread of Life sermon at Capernaum--they both involve faith, or rather the inconsistent faith two of the apostles. In John 6:6, Jesus tests Philip's faith in the feeding of the 5000--the only public miracle mentioned in all four Gospels. Jesus asks Philip how can they buy enough food for the crowd and Philip, not trusting Jesus, looks at it only from a material viewpoint (the cost) and is at an utter loss. Jesus then multiples the scant amount of fishes and bread they do have to feed the 5000 (with plenty of leftovers). This incident occurs the right before Jesus' entry into Capernaum and the crowd was still excited over it (6:26).
The second incident is Jesus calming the storm and reprimanding Peter for his lack of faith (Matt 14:31). Peter was almost certainly still feeling guilty from his Master's rebuke and probably wanting to make up for it.
In both cases the disciples, "in the moment" doubted Jesus actually doing something. Philip and Peter both looked at the situations materially, or "carnally". In both cases Jesus showed the laws of nature were subject to his will.
Jesus walks into Capernaum, and he chides the crowd for only seeing the obvious physical fact of the multiplied loaves which filled their bellies (6:26). Throughout the discourse, looking at the world "as it is" (materially, carnally) will consistently counter faith in Jesus' word. This discourse, perhaps even more than the bombshell "I AM" of 8:58, is the turning point of John's gospel. Jesus masterfully segues from his chiding his followers to present them an "either-or" choice of staggering contrast: "either believe what I say no matter what your material senses or reason ("the flesh") tell you or have no part in me."
This stark choice doesn't come out of nowhere. For nearly two years, Jesus had been building up his credibility and his authority. He backed up his words with deeds. Many of his followers were witnesses to Jesus' miraculous "signs". He didn't just do the healings and exorcisms expected of a holy man, Jesus went way beyond those into transformations of matter (water into wine) commanding nature (calming the storm) and the even raising the dead. He also was such a speaker that people dropped their everyday work lives to listen to him for hours, forgetting even to bring lunch--and another miracle feeds them to abundance. If ever a man was "it", the awaited King, the Messiah, Jesus was the one. But then...
The discourse is marked by Jesus' repeated "double-amen’s" ("Truly" in the RSV, "Verily" in some others). "Amen" is Hebrew for "so be it", "so it is", "this is so", "it's a fact", "this is the way it really is". When Jesus leads off with a double-amen, he is saying, "this is really, REALLY important". When his incredulous listeners question what Jesus just said, his double-amen is an emphasized confirmation his listeners heard and understood correctly.
In verse 27, Jesus's segue continues from the crowd being excited over earthly bread (however miraculously produced) to the necessity of consuming food which gives eternal life, which the "Son of Man", authorized by God the Father, will give to them.
The crowd, which includes many long-term followers, has no problem with this (6:28). They certainly want to cooperate with God to get eternal life; they just want to know "how".
6:29 is one of the verses which deniers of the Real Presence use. "Jesus answered them, "This is the word of God, that you believe in him who he has sent". If this is all Jesus had said regarding "food" which gives eternal life, the Catholic Church would not teach the Real Presence. What follows in the give and take between Jesus and his questioners makes it clear what Jesus means by "believe".
The questioners still had the multiplication of fishes and loaves still in mind along with food that provides eternal life. In verses 30-31 they ask Jesus for a sign, akin to the manna that fed the Israelites in the wilderness. They had experienced Jesus' miracle of multiplication-- a very real, tangible thing. Now Jesus was talking about food from God, through the Son of Man (Jesus). The last time God had preserved the life of Israel by food, it had been the manna of the Exodus--another real, tangible thing. So the "sign" they are asking for must be real and tangible too. Jesus himself used “sign” in a real material sense, as in his referring to the “sign of Jonah” (Matt 12:38-40), referring to his own burial, as well as his Second Coming (Matt 24:30-31).
Verses 32-33 Jesus gives the crowd a "heads up!" with a double-amen.
"Truly, truly it was not Moses who gave you the bread from heaven..." (Moses interceded for manna to sustain earthly life, the actual "bread from heaven" is the food which gives eternal life which manna could not do)"...my Father gives you the bread from heaven. For the bread of God is that which comes down from heaven and gives life to the world"
Jesus is promising something far, far greater than manna. (However manna prefigures the Eucharist in that it was created by God’s action and it did sustain life.)
The crowd is primed, demanding in verse 34...”Lord, give us this bread always".
The discourse begins in earnest with verses 35-40:
"I am the bread of life; he who comes to me shall not hunger and who believes in me shall not thirst. But I said to you that you have seen me and yet do not believe..."
Read that passage again; Jesus not only equates himself with the means to eternal life, "the bread from heaven", but he also says to the crowd they have seen him and what he has done and they don't believe (why they don't believe is right next).
"...For I have come down from heaven, not to do my own will, but the will of him who sent me...for this is the will of my Father, that everyone who sees the Son and believes in him should have eternal life and I will raise him up on the last day"
Here "it" is, though it will take a few more clarifications from Jesus to rule out any ambiguity, any waffling that his listeners can retreat in comfort to. He's used the "Son of Man" before as his most common self reference--and for his Jewish audience, that points to the exalted, celestial "Son of Man" found in Isaiah. Now Jesus has outright claimed "I have come down from heaven..." and many in the crowd can't take it:
"...murmured at him, because he said "I am the bread which came down from heaven". They said, "Is this not Jesus, the son of Joseph, whose father and mother we know? How can he now say, "I have come down from heaven?"
Deniers of the Real Presence, both historical and contemporary, tend to gloss over that passage and how it applies to what Jesus says from here on. The listeners can't ignore what they just heard compared to what they see: they look at Jesus with their "natural" (the "flesh") senses and reason. All they see is a human man, who they know was born of a human woman, but now this man claims he came down from heaven.
What his listeners have just heard is the proclamation of the Incarnation. Jesus has just claimed to be a celestial being, the "Son of Man" and co-identified with the "Bread of Life" which is the means God provides for the resurrection from the dead and eternal life. He has not only identified himself repeatedly as the "Son of Man" but also explicitly and particularly as the Son of God, the Father. Even if the listeners have not logically followed these claims to the conclusion of Jesus' full-divinity, they are upset. To their reason and senses, Jesus is either speaking lies or lunacy. Like Peter and like Philip, they have forgotten all they’ve seen Jesus do. They do not have "faith" in what Jesus is claiming. Jesus's humanity is all they see and from that they do not believe his Incarnation.
Still, even at this point, if this is all Jesus said about being the "Bread of Life", the Catholic Church would not teach the doctrine of the Real Presence in the Eucharist. Jesus might be speaking metaphorically, like he did in two "food" metaphors (4:31-34, Matt 16: 5-12)--but what follows repeatedly rules this possibility out.
"Jesus answered them, "Do not murmur among your selves. No one can come to me unless the Father who sent me draws him; and I will raise him up on the last day; It is written by the prophets "And they shall be taught by God"..."(6:43-45)
Jesus again claims he will be the agent of the resurrection and his words are, de facto, God's. If you believe in Jesus it's only because the Father brought you to him.
"...Every one who has heard and learned from the Father comes to me. Not that any one has seen the Father, except him who is from God; he has seen the Father" (6:45-46)
Not only is Jesus again claiming to be from heaven, he is claiming a privilege denied to the Seraphim before heaven's throne. He also is claiming that any truth humanity knows about God the Father involved Jesus as well. We are not quite to the declaration of 8:58 but we and the listeners at Capernaum are very, very close to it. It does not take much imagination to envision the crowd being very noisy and restless, for these are strict monotheists being told by a local boy that he (Jesus) is not just a prophet above all prophets (Moses and Elijah included), he is even above the highest angels! Just who does Jesus think he is? 
"Truly, truly [Amen, amen; "so it is, so it is", "this is so, this is so", "it's a fact, it's a fact", "this is the way it really is, this is the way it really is"] I say to you, he who believes has eternal life. I am the bread of life." (6:47-48)
After this point, there are no metaphorical turns of belief allowed; it all gets viscerally literal. It will no longer be a vague "belief" in Jesus, it will be as specific as a punch to the gut--Indeed some of his listeners must have gotten quite queasy. Just as one cannot "just believe" in food and not do anything with it (e.g., refuse to eat it) and survive physically neither can one just "believe" in Jesus.
"Your fathers ate the manna in the wilderness and they died. This is the bread which comes down from heaven, that a man may eat of it and not die. I am the living bread which came down from heaven; if any one eats of this bread, he will live for ever; and the bread I give for the life of the world is my flesh" (6:49-51).
This is Jesus' FIRST explicit declaration one must literally eat his flesh, the "living bread which came down from heaven" in order to have eternal life. Multiple times Jesus has said, one must eat the "bread of heaven" to have eternal life, and he, Jesus, came down from heaven, and twice now that he, Jesus, IS the "bread of heaven” Perhaps most importantly, in verse 51, Jesus explicitly identifies this heavenly bread, “my flesh”, with the same flesh he will sacrifice at Calvary. Somehow, Jesus wants us to literally eat this very same sacrificial flesh as the means to eternal life.
"The Jews then disputed among themselves, saying "How can this man give us his flesh to eat?" (6:52)
The outrage and the disgust clearly come across the span of almost 2000 years. You can almost see the listeners looking at each other, asking "did you hear that?--you did?! I heard it too!" Many of in the crowd were disciples, had been with Jesus for almost two years, they knew his turns of phrase, when he was using metaphor and simile. In no way was this presented as a parable, this was a strait out declaration. All of Jesus' listeners shared the same language and culture with him; they clearly understood what Jesus was saying. Jesus was speaking literally about the necessity of "eating his flesh" and the crowd understood him literally.
"Truly, truly [Amen, amen, so it is, so it is,...] 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 (6:53-55)
THREE declarations that reinforce the literal meaning of "flesh", "blood", "eat" and "drink"--further reinforced with a double-amen to confirm the listeners heard and understood Jesus correctly. In the Koine Greek of the Gospel, the writer now switches from "phago", which means "eat", to "trogo" which means "to gnaw, to chew". This was NEVER the language of metaphor or of other symbolism to begin with and switching to “chewing” intensifies the literal meaning.
Jesus is just too good a speaker not to take into account the limitations of his listeners. When his listeners mistook something he said as literal, he corrected their false understanding (John 3:3-5. 11:11-14, 8:21-23, 8:31-36, 6:32-36, Matt 16:5-12, Matt 19:24-26). When his listeners correctly understood something he said as literal, Jesus confirms their understanding and repeats what he said (John 8:56-59, 6:41-51, Matt 9:2-6). Nowhere in this discourse (or privately to the apostles) does Jesus offer any alternative symbolic meaning to "flesh", "blood", "eat" and "drink". Neither does the gospel writer offer any explanation, like he does in 2:21 and 7:38.
Besides, there already was an alternative and figurative meaning to "eat someone's flesh and drink their blood" in Aramaic, the language Jesus spoke (as well as in Hebrew, Koine Greek, Modern Greek, and Arabic). To apply it to what Jesus said is to make him speak complete nonsense, because it means "to assault, persecute, slander, and destroy". It is used as such several times in scripture (Ps 27:2, Isa 9: 18-20, Isa 49:26, Mica 3:3, 2 Sam 23: 15-17, and Rev 17:6, 16). So unless you really want to claim Jesus proclaimed "he who attacks me and slanders me shall have eternal life" you, like the crowd at Capernaum, are left with the literal meaning only. If Jesus did not provide an alternative symbolic meaning, then the literal meaning he repeatedly confirmed or the common figurative meaning are the only choices.
Sometime during the discourse, Jesus and his listeners have moved into the synagogue (6:59). It’s still a public address, but the context of the setting is now even more an official pronouncement and teaching--remember Jesus spoke of the Pharisees giving binding commands from the "chair of Moses" (Matt 23:2-3) we should consider this sermon as "ex cathedra" as well.
"He who eats of my flesh and drinks of my blood abides in me and I in him. As the living Father sent me and I live because of the Father so he that eats me will live because of me. This is the bread that came down from heaven, not such as the fathers ate and died; he who eats this bread will live for ever" (6:56-58)
Here are THREE MORE repetitions, making SIX in a row re-affirming the literalness of the command to eat Jesus' flesh and drink his blood as a necessity for eternal life. The listeners, disciples and others, already had problems with Jesus' claim to literally come down from heaven and they have it now with this "eat and drink" command.
Likewise, all a denier of the Real Presence sees is bread or wine, no matter what Jesus claims. Jesus claimed literally to come down from heaven, Jesus then repeatedly claimed eternal life is dependent of literally eating his flesh and drinking his blood. Jesus didn’t soften or qualify his claim of Incarnation and likewise he didn’t qualify "eating" and "drinking". The claims are not only parallel they are mutually interdependent. If you want to deny the literal demand to "eat" and "drink" you HAVE to deny he literally came down from heaven.
At least the crowd in the synagogue was consistent:
"Many of his disciples when they heard it, said "This is a hard saying; who can listen to it? But Jesus, knowing in himself that his disciples murmured at it, said to them, "Do you take offense at this? Then what if you were to see the Son of man ascending to where he was before?" (6:60-62)
Jesus knows that many of his followers are on the edge. He reminds them of his claim of heavenly origin by now claiming that is where he will return (The Ascension). Jesus is pointing out many of them can only believe if outward evidence is constantly before them--in other words, they lack "faith" in Jesus and what he says.
Here is where the discourse now concentrates on faith. It directly relates to the Real Presence, for just as Jesus expected his followers to believe he literally descended from heaven, regardless of the fact of being born of a woman and looking only like a human man, he declares you must literally eat his flesh and drink his blood if you are to have eternal life. How? Because Jesus said so. Jesus already provided sufficient evidence of his credibility (and he'll supply much more, like the Resurrection and the Ascension) but you have to have faith, constant loyalty in his word, rather than what you see in the moment.
"It is the spirit that gives life, the flesh is of no avail; the words I have spoken to you are spirit and life" (6:63)
Here is where deniers of the Real Presence go wrong in a big way. The deniers claim Jesus is now saying the same "flesh" he's been commanding his followers to eat as the means to eternal life is now useless. Never mind yet the particulars of "flesh"; claiming Jesus is deliberately speaking a self-contradictory sermon is the same as claiming Jesus is wasting everyone's time and attention.
To claim Jesus spent this entire time upsetting people by speaking figuratively and they were too dense to "get it" you have to ignore the fact Jesus SIX times reinforced their literal understanding of "eat my flesh and drink my blood". Clearly, there must be a distinction between Jesus' "flesh" which gives eternal life and "the flesh" which is useless.
Also, NO WHERE in scripture is "spirit" equated with "symbolic". God the Father is pure spirit and is real and is not a symbol. God the Holy Spirit is real and not a symbol. The angels and devils are spirits and are quite real. The human soul is spirit and is real. To believe the things of spirit you believe in things that are not discernable with the natural senses--you believe with faith.
So here in the synagogue, Jesus is now contrasting the man who sees things only with “the flesh”, with purely human thoughts and desires, to the man who sees things with “spirit”, with his thoughts and desires elevated by God’s grace. There are several scriptural verses which support this understanding of “the flesh” vs. “spirit”, most especially in 1st Corinthians and Romans:
“The unspiritual man does not receive the gifts of the Spirit of God for they are folly to him, and he is not able to understand them because they are spiritually discerned. The spiritual man judges all things but is himself to be judged by no one. “For who has known the mind of the Lord so as to instruct him?” But we have the mind of Christ. But I, brethren, could not address you as spiritual men, but as men of the flesh, as babes in Christ. I fed you with milk, not solid food; for you were not ready for it; and even yet you are not ready, for you are still of the flesh. For while there is jealousy and strife among you, are you not of the flesh and behaving like ordinary men? For when one says, “I belong to Paul” and another “I belong to Apollos”, are you not merely men?” (1 Corinthians 2:14—3:4)
“For those who live according to the flesh set their minds on the things of the flesh, but those who live according to the Spirit set their minds on the things of the Spirit. To set the mind on the flesh is death, but to set the mind on the Spirit is life and peace. For the mind set on the flesh is hostile to God; it does not submit to God’s law, indeed it cannot; and those who are in the flesh cannot please God. But you are not in the flesh, you are in the Spirit, if the Spirit of God really dwells in you. Anyone who does not have the Spirit of God does not belong to him.” (Romans 8:1-13)
Other scripture confirms this consistent understanding of “THE flesh” vs. “Spirit” (Matt 26:41, John 3:6, Gal 3:3,4:29, 5:13-26, Rom 7:5-6,25, 13:14).
Back to the discourse, Jesus is flat out calling many of the crowd unbelievers. They look at Jesus and all they see is a man. They do not believe he is the "Son of man" descended from heaven and they certainly do not believe Jesus is the "bread from heaven" which they must literally consume by eating his flesh and drinking his blood. Jesus has declared them lacking in faith, lacking in spirit, possessed by purely natural thoughts and desires. He told them clearly and repeatedly what to believe and they just should have done so. Jesus never asked them to "understand", only to trust his word.
"...the words I have spoken are spirit and life. But there are some among you that do not believe". For Jesus knew from the first who those were that did not believe and who it was that should betray him. And he said", "This is why I told you that no one can come to me unless it is granted to him by the Father" (6:63-65)
At the conclusion of this incredible "take me or leave me" sermon, the gospel writer links not believing in Jesus as the literal "bread of life" to the betrayal of Jesus by Judas Iscariot.
"After this many of his disciples drew back and no longer went about with him." (6:66)
They at least were honest, unlike Judas who continued to hang around for reasons other than believing in Jesus. One can imagine the apostles huddled together in the synagogue while the others streamed out, some of those leaving undoubtedly with some rude words of dismissal. Many of those leaving must have been among the 70 "ambassadors" Jesus appointed in Luke 10. They all were leaving Jesus (at least temporarily) over a matter of clearly taught doctrine, a "great apostasy" over Jesus teaching the Real Presence. Jesus himself makes no attempt to stop them, explain himself further, and correct any misconceptions. He spoke literally and was understood literally. As Jews who avoided eating animal blood per Mosaic Law, what Jesus just told them was way too much for their intellect and their stomachs. If Jesus had made any indications all this was a metaphor or a symbol, they could have stayed with him. But the Master was determined to make this an ultimatum.
"Jesus said to the twelve, "Will you also go away?" (6:67)
No post-parable explanation here. Jesus had given everybody a "take-this-or-leave-me" choice and most of them had walked. Now he was explicitly doing the same with the apostles.
"Simon Peter answered him, "Lord, to whom shall we go? You have the words of eternal life and we have believed and have come to know you are the Holy One of God" (6:68-69)
Perhaps with a quaver in his voice, Peter steps up to the plate, and as at Caesarea Philippi (Matt 16:16), nails a line drive into center field. Peter clearly doesn't "understand" how he is to "eat the body" and "drink the blood", only he is to trust Jesus utterly and simply at his word and perhaps some clarification will come later, and perhaps not. You are to trust Jesus as a child trusts his father, not with your intellect or stunted imagination, but with your heart.
Faith in the Real Presence of the Eucharist requires this sort of faith. It is no accident that the "Bread of Life" discourse seamlessly turns into the sermon on faith in Christ's word--faith above appearances, above "fleshly" desires and preferences.
“Jesus answered them, “Did I not choose you, the twelve, and one of you is a devil?” He spoke of Judas, the son of Simon Iscariot, for he, one of the twelve, was to betray him.” (6:70-71)
Again, Judas’ betrayal is linked with his lack of faith in Jesus’ word. Jesus had worked so many material “signs” before Judas’ eyes and all these miracles, like they so often do in scripture, fail to convince those who trust themselves above God. Now Jesus is demanding you believe him about incredible claims with NO material signs, and Judas fails the test.
Throughout John's gospel, the writer constantly stresses the need for believing Christ above one's desires and one's preferred "reasoning". In many ways, the gospel is a polemical response to the first intrusions of Gnosticism into the 1st Century Church. The opening prologue, 1:1-18 seems to be patterned after an early Gnostic "hymn" but uses the form to deliver a point-by-point refutation of Gnostic claims about Christ, creation, and the Incarnation. When John wrote the majority of his gospel circa 69-70 AD, the Church had been celebrating the Eucharist, the "Lord's Supper", close to 40 years. Gnostics, largely viewing creation (e.g. physical matter) as "corrupted emanations" found the idea of the Sacraments using physical matter as conduits of Grace (baptismal water, Eucharistic "species", and anointing oil) repugnant. Since many Gnostics held that Christ on Earth was only some phantasmal presence and not physically incarnated (Docetism), the idea that Christ was also fully and physically present in the Eucharist was an additional horror. John presents the Bread of Life discourse and the subsequent sermon on faith as an ultimate disproval of Gnostic claims by Jesus’ own declaration.
Modernist New Testament scholarship commonly claims the Bread of Life discourse is not about the Eucharist because John doesn’t describe the Eucharist in his Last Supper account. This claim in turn rests on the unsupported assertion that the author of the gospel was at least unfamiliar, if not totally unaware, of any of the synoptic gospels. If the gospel's author didn’t describe the Eucharist, then it wasn't important to him, hence the 6th chapter cannot be about the Eucharist. This supposition is further based on several other assertions with no evidence, including the gospels were “community creations” of isolated churches, rather than the work of individuals close to the events described, and that these “believing communities” had little or no interest in actual historical events regarding their Savior’s life. Not only do these assertions upon assertions ignore what we actually know about the 1st Century Roman Empire (travel was common and the mail delivery secure) they also actively contradict the testimony of the Early Church Fathers regarding to authorship and dating of the gospels and epistles. From Clement of Alexandria, we learn that John was quite aware of the synoptics, and composed his gospel (assisted by another apostle, Andrew) to produce a more “spiritual” gospel—meaning one with Jesus’ strait forward sermons and theological declarations about the things of spirit; John recounting these, in large part, to refute the Gnostics. The fact John consistently did not cover the same ground as the synoptic gospels is strong evidence he was intimately familiar with them, which would not have been the case if he (or for the utterly suppositional "Johanine Community") had been composing it only from a common stream of oral testimony.
The discounting and ignoring of the Early Church Fathers is a signature of Modernist scholarship, largely inherited from Protestant antecedents (be it mainstream, evangelical, or fundamentalist sources). The "elephant in the living room" for Protestant theologians was and is that the Fathers were undeniably Catholic, teaching distinctive Catholic doctrines right alongside doctrines Protestantism agrees with. Too deep a study of Patristics has always been a problematic area for Protestant theologians, as witnessed by many prominent conversions to Catholicism, especially that of John Henry Newman and other patristic scholars in the 19th Century's "Oxford Movement". Even Martin Luther, who had a very high regard for the Fathers regarding the issue of the Real Presence, claimed the Fathers hardly cited John 6 in their universal support of the doctrine.
Even if explicit attributed citations of John 6 are sparse in patristic defense of the Real Presence, the Fathers use the discourse’s very concrete language (especially "Flesh", "food", and "drink”) as much as they quote from the Last Supper accounts in the synoptic gospels or 1st Corinthians.
Ignatius of Antioch, a disciple of the very same John the Evangelist, also had to contend with Gnostic infiltrators and their denial of Christ's presence in the Eucharist. Ignatius in particular uses John’s vocabulary:
"Take note of those who hold heterodox opinions on the grace of Jesus Christ which have 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 the Father, in his goodness, raised up again" (Letter to the Smyrnaeans, circa 107 AD)
"I have no taste for corruptible food nor for the pleasures of this life. I desire the bread of God, which is the Flesh of Jesus Christ, who was of the seed of David; and for drink I desire his Blood which is love incorruptible." (Letter to the Romans, circa 107 AD)
Another very early Father is the Roman lawyer, Justin Martyr, who wrote to Emperor Antonitus Pius in what was essentially a legal brief, trying to correct any false impressions the Emperor might have about the faith. It is notable Justin took pains in describing the Eucharist because a false understanding of the doctrine of the Real Presence as "cannibalism" was being leveled against the Church. If the Eucharist at this early point was understood by the faithful as "symbolic", Justin could easily have used that explanation to show how ridiculous the slander was. Instead, Justin goes ahead with the much harder task of confessing the Real Presence:
"We call this food Eucharist; and no one is permitted to partake of it, except one who believes our teaching to be true...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 nourished, is both the Flesh and Blood of that incarnated Jesus." (First Apology, circa 150 AD)
Numerous and unanimous examples from the Fathers could be cited to further prove the early Church understood Jesus as the literal "bread from heaven" provided his very flesh and his very blood to be consumed by believers in the Eucharist, and this "living bread" was the very same flesh and blood offered at Calvary. It truly begs credulity to accept Luther’s tenuous and strained exegesis of John 6 as something apart from the Sacrament. The Jews at Capernaum understood Jesus literally and rejected him because they took him at his repeated word. Jesus not only did nothing to correct any misunderstanding of any intended other message (like sola fide), he just reinforced his listener's literal understanding of "I came down from heaven so you may eat my flesh and drink my blood and you HAVE to believe me on this if you want eternal life." Yes, John 6 concludes with a sermon on faith, but it's faith in something as real as a promised kiss or the coming spring's warming sun.
"Faith is to believe what you do not see; the reward of faith is to see what you believe." --St. Augustine of Hippo
 "I would rather drink actual blood with a Papist than drink wine with a Zwinglian”—Martin Luther
 As one can see, not much has changed in 2000 years.
 Latin, “from the chair”, derived from 1st century Jewish usage
 The internal evidence of John as well as the testimony of the Early Church Fathers supports this dating. The claim of “Late Composition” of the Gospels and Epistles (along with other largely unsupported theories, such as “Q”, “Markan priority”, “community composition, and “psuedographic authorship”) is more of an inherited habit of modern (after 1800) New Testament scholarship than a matter of evidence-based findings. The bias to “de-mythologize” the New Testament (e.g., remove supernatural events and claims) was born from the irreligious motives of the Enlightenment-era’s Deist “scholars”, called “scientific”, and passed on as secular orthodoxy. These largely unexamined guiding assumptions penetrated mainstream Protestant seminaries in the later 19th century (provoking in reaction the Fundamentalist movement) and after the “anti-modernism oath” was revoked by the Vatican in the 1950s, it entered into Catholic theology schools as well. Many very orthodox Catholic scholars cite Late Composition dates because that is what they were taught from their professors (many of them either secular or liberal Protestants) and because supporting a more traditional dating and authorship is seen as “uncritical”. However, “uncritical” seems to be the very attitude of modernist scholars towards the theories of “Late Composition” and the rest of their inherited traditions.
“The Christianity of history is not Protestantism. If there ever was a safe truth, it is this. And Protestantism has ever felt it so…This is shown in the determination…of dispensing with historical Christianity altogether, and of forming a Christianity from the Bible alone: men never would have put it [historical Christianity] aside unless they had despaired of it…To be deep in history is to cease being a Protestant.” John Henry Newman, Essay on the Development of Christian Doctrine
 When rabbis, without the interpretive bias of Protestantism, examine the New Testament, they consistently interpret John 6 as overwhelmingly literal and thereby problematic on that basis.