After these things Jesus went over the Sea of Galilee, which is the Sea of Tiberias. Then a great multitude followed Him, because they saw His signs which He performed on those who were diseased. And Jesus went up on the mountain, and there He sat with His disciples. John 6:1-3.
Note: People were following Jesus Christ for the wrong reasons.
 
Now the Passover, a feast of the Jews, was near. Then Jesus lifted up His eyes, and seeing a great multitude coming toward Him, He said to Philip, “Where shall we buy bread, that these may eat?” But this He said to test him, for He Himself knew what He would do. John 6:4-6.
Note: Jesus Christ wanted His disciples to think spiritually.
 
Philip answered Him, “Two hundred denarii worth of bread is not sufficient for them, that every one of them may have a little.” One of His disciples, Andrew, Simon Peter’s brother, said to Him, “There is a lad here who has five barley loaves and two small fish, but what are they among so many?” John 6:7-9.
Note: The disciples were still thinking of the material world.
 
Then Jesus said, “Make the people sit down.” Now there was much grass in the place. So the men sat down, in number about five thousand. And Jesus took the loaves, and when He had given thanks, He distributed them to the disciples, and the disciples to those sitting down; and likewise of the fish, as much as they wanted. So, when they were filled, He said to His disciples, “Gather up the fragments that remain, so that nothing is lost.” Therefore, they gathered them up, and filled twelve baskets with the fragments of the five barley loaves which were left over by those who had eaten. Then those men, when they had seen the sign that Jesus did, said, “This is truly the Prophet who is to come into the world.” John 6:10-14.
Note: Jesus Christ performed a miracle so people would believe.
 
Therefore, when Jesus perceived that they were about to come and take Him by force to make Him king, He departed again to the mountain by Himself alone. Now when evening came, His disciples went down to the sea, got into the boat, and went over the sea toward Capernaum. And it was already dark, and Jesus had not come to them. Then the sea arose because a great wind was blowing. So, when they had rowed about three or four miles, they saw Jesus walking on the sea and drawing near the boat; and they were afraid. But He said to them, “It is I; do not be afraid.” Then they willingly received Him into the boat, and immediately the boat was at the land where they were going. John 6:15-21.
Note: Jesus Christ performed a miracle so His disciples would believe.
 
On the following day, when the people who were standing on the other side of the sea saw that there was no other boat there, except that one which His disciples had entered, and that Jesus had not entered the boat with His disciples, but His disciples had gone away alone— however, other boats came from Tiberias, near the place where they ate bread after the Lord had given thanks— when the people therefore saw that Jesus was not there, nor His disciples, they also got into boats and came to Capernaum, seeking Jesus. And when they found Him on the other side of the sea, they said to Him, “Rabbi, when did You come here?” John 6:22-25.
Note: False followers were seeking free food and material things.
 
Jesus answered them and said, “Most assuredly, I say to you, you seek Me, not because you saw the signs, but because you ate of the loaves and were filled. Do not labor for the food which perishes, but for the food which endures to everlasting life, which the Son of Man will give you, because God the Father has set His seal on Him.” John 6:26-27.
Note: True followers of Jesus Christ will be spiritually minded.
 
Then they said to Him, “What shall we do, that we may work the works of God?” Jesus answered and said to them, “This is the work of God, that you believe in Him whom He sent.” John 6:28-29.
Note: Are you doing the work of God and believing in Jesus Christ?
 
Therefore, they said to Him, “What sign will You perform then, that we may see it and believe You? What work will You do? Our fathers ate the manna in the desert; as it is written, ‘He gave them bread from heaven to eat.’” Then Jesus said to them, “Most assuredly, I say to you, Moses did not give you the bread from heaven, but My Father gives you the true bread from heaven. For the bread of God is He who comes down from heaven and gives life to the world.” Then they said to Him, “Lord, give us this bread always.” And Jesus said to them, “I am the bread of life. He who comes to Me shall never hunger, and he who believes in Me shall never thirst. But I said to you that you have seen Me and yet do not believe. John 6: 30-36.
Note: Unbelievers will only think materially not spiritually.
 
All that the Father gives Me will come to Me, and the one who comes to Me I will by no means cast out. For I have come down from heaven, not to do My own will, but the will of Him who sent Me. This is the will of the Father who sent Me, that of all He has given Me I should lose nothing, but should raise it up at the last day. And this is the will of Him who sent Me, that everyone who sees the Son and believes in Him may have everlasting life; and I will raise him up at the last day.” John 6:37-40.
Note: Believers in Jesus Christ are doing the will of God.
 
The Jews then complained about Him, because He said, “I am the bread which came down from heaven.” And they said, “Is not this Jesus, the son of Joseph, whose father and mother we know? How is it then that He says, ‘I have come down from heaven’?” John 6:41-42.
Note: Unbelievers will not believe in the deity of Jesus Christ.
 
Jesus therefore answered and said to them, “Do not murmur among yourselves. No one can come to Me unless the Father who sent Me draws him; and I will raise him up at the last day. It is written in the prophets, ‘And they shall all be taught by God.’ Therefore, everyone who has heard and learned from the Father comes to Me. Not that anyone has seen the Father, except He who is from God; He has seen the Father. Most assuredly, I say to you, he who believes in Me has everlasting life.” John 6:43-47.
Note: Believers in Jesus Christ has everlasting life.

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.” These things He said in the synagogue as He taught in Capernaum. Therefore, many of His disciples, when they heard this, said, “This is a hard saying; who can understand it?” John 6:53-60.
Note: Jesus Christ talks of cannibalism to get rid of free food false followers.
Cannibalism is mentioned several times in Scripture (Leviticus 26:29; Deuteronomy 28:53-57; Jeremiah 19:9; Lamentations 2:20; 4:10; Ezekiel 5:10), but in each case, the practice is regarded as a horrible curse and inhuman act of desperation. Moses and other prophets predicted that, if the Israelites forsook God, they would fall into such awful degradation as to cannibalize their own children. These harrowing prophecies were fulfilled during the siege of Samaria during the reign of King Jehoram (2 Kings 6:28-29). Cannibalism was the physical horror which accompanied the spiritual horror of apostasy. gotquestions.com
 
When Jesus knew in Himself that His disciples complained about this, He said to them, “Does this offend you? What then if you should see the Son of Man ascend where He was before? It is the Spirit who gives life; the flesh profits nothing. The words that I speak to you are spirit, and they are life.” John 6:61-63.
Note: Jesus Christ returns the conversation to everlasting life.
 
“But there are some of you who do not believe.” For Jesus knew from the beginning who they were who did not believe, and who would betray Him. And He said, “Therefore I have said to you that no one can come to Me unless it has been granted to him by My Father.” From that time many of His disciples went back and walked with Him no more. John 6:64-66.
Note: Jesus Christ succeeded in eliminating free food false followers.
 
Then Jesus said to the twelve, “Do you also want to go away?” But Simon Peter answered Him, “Lord, to whom shall we go? You have the words of eternal life. Also, we have come to believe and know that You are the Christ, the Son of the living God.” Jesus answered them, “Did I not choose you, the twelve, and one of you is a devil?” He spoke of Judas Iscariot, the son of Simon, for it was he who would betray Him, being one of the twelve. John 6:67-71.
Note: True believers will follow and confess Jesus Christ.
 

What Catholics Believe about John 6
(Catholic Answers – Catholic.com)

 
For millions of non-Catholic Christians, Jesus was using pure symbolism in John 6:53 when he declared to his followers, “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.” The reasons non-Catholics give can usually be boiled down to these: First, a literal interpretation would make Christians into cannibals. Second, Jesus claims to be a “door” in John 10:9 and a “vine” in John 15:5. Do Catholics believe they must pluck a leaf from Jesus the vine or oil the hinges on Jesus the door to get into heaven? So the non-Catholic claims Jesus is using metaphor in John 6, just as he does elsewhere in the Gospels.

Catholic Cannibals?

The charge of cannibalism does not hold water for at least three reasons. First, Catholics do not receive our Lord in a cannibalistic form. Catholics receive him in the form of bread and wine. The cannibal kills his victim; Jesus does not die when he is consumed in Communion. Indeed, he is not changed in the slightest; the communicant is the only person who is changed. The cannibal eats part of his victim, whereas in Communion the entire Christ is consumed—body, blood, soul, and divinity. The cannibal sheds the blood of his victim; in Communion our Lord gives himself to us in a non-bloody way.   

Second, if it were truly immoral in any sense for Christ to give us his flesh and blood to eat, it would be contrary to his holiness to command anyone to eat his body and blood—even symbolically. Symbolically performing an immoral act would be of its nature immoral.

Moreover, the expressions to eat flesh and to drink blood already carried symbolic meaning both in the Hebrew Old Testament and in the Greek New Testament, which was heavily influenced by Hebrew. In Psalm 27:1-2, Isaiah 9:18-20, Isaiah 49:26, Micah 3:3, and Revelation 17:6-16, we find these words (eating flesh and drinking blood) understood as symbolic for persecuting or assaulting someone. Jesus’ Jewish audience would never have thought he was saying, “Unless you persecute and assault me, you shall not have life in you.” Jesus never encouraged sin. This may well be another reason why the Jews took Christ at his word.

Not Metaphorically Speaking

If Jesus was speaking in purely symbolic terms, his competence as a teacher would have to be called into question. No one listening to him understood him to be speaking metaphorically. Contrast his listeners’ reaction when Jesus said he was a “door” or a “vine.” Nowhere do we find anyone asking, “How can this man be a door made out of wood?” Or, “How can this man claim to be a plant?” When Jesus spoke in metaphor, his audience seems to have been fully aware of it.

When we examine the surrounding context of John 6:53, Jesus’ words could hardly have been clearer. In verse 51, he plainly claims to be “the living bread” that his followers must eat. And he says in no uncertain terms that “the bread which I shall give . . . is my flesh.” Then, when the Jews were found “disput[ing] among themselves, saying, ‘How can this man give us his flesh to eat?’” in verse 52, he reiterates even more emphatically, “Truly, truly, I say unto you, unless you eat the flesh of the Son of man and drink his blood, you have no life in you.”

Compare this with other examples in Scripture when followers of the Lord are confused about his teaching. In John 4:32, Jesus says: “I have food to eat of which you do not know.” The disciples thought Jesus was speaking about physical food. Our Lord quickly clears up the point using concise, unmistakable language in verse 34: “My food is to do the will of him who sent me, and to accomplish his work” (see also Matthew 16:5-12).   

Moreover, when we consider the language used by John, a literal interpretation—however disturbing—becomes even more obvious. In John 6:50-53 we encounter various forms of the Greek verb phago, “eating.” However, after the Jews begin to express incredulity at the idea of eating Christ’s flesh, the language begins to intensify. In verse 54, John begins to use trogo instead of phago. Trogo is a decidedly more graphic term, meaning “to chew on” or to “gnaw on”—as when an animal is ripping apart its prey.

Then, in verse 61, it is no longer the Jewish multitudes, but the disciples themselves who are having difficulty with these radical statements of our Lord. Surely, if he were speaking symbolically, he would clear up the difficulty now among his disciples. Instead, what does Jesus do? He reiterates the fact that he meant just what he said: “Do you take offense at this? Then what if you were to see the Son of man ascending where he was before?” (61-62). Would anyone think him to have meant, “What if you were to see me symbolically ascend?” Hardly! The apostles, in fact, did see Jesus literally ascend to where he was before (see Acts 1:9-10).

Finally, our Lord turns to the twelve. What he does not say to them is perhaps more important than what he does say. He doesn’t say, “Hey guys, I was misleading the Jewish multitudes, the disciples, and everyone else, but now I am going to tell you alone the simple truth: I was speaking symbolically.” Rather, he says to them, “Will you also go away?” (v. 67). This most profound question from our Lord echoes down through the centuries, calling all followers of Christ in a similar fashion. With St. Peter, those who hear the voice of the Shepherd respond: “Lord, to whom shall we go? You have the words of eternal life” (v. 68).   

Spirit vs. Flesh

John 6:63 is the one verse singled out by Protestant apologists to counter much of what we have asserted thus far. After seeing the Jews and the disciples struggling with the radical nature of his words, our Lord says to the disciples and to us all: “It is the spirit that gives life, the flesh is of no avail; the words that I have spoken to you are spirit and life.” Protestants claim Jesus here lets us know he was speaking symbolically or “spiritually” when he said “the spirit gives life, the flesh is of no avail.” See? He is not giving us his flesh to eat because he says “the flesh is of no avail.” How do we respond? We can in several ways.

1) If Jesus was clearing up the point, he would have to be considered a poor teacher: Many of the disciples left him immediately thereafter because they still believed the words of our Lord to mean what they said.

2) Most importantly, Jesus did not say, “My flesh is of no avail.” He said, “The flesh is of no avail.” There is a rather large difference between the two. No one, it is safe to say, would have believed he meant my flesh avails nothing because he just spent a good portion of this same discourse telling us that his flesh would be “given for the life of the world” (Jn 6:51, cf. 50-58). So to what was he referring? The flesh is a New Testament term often used to describe human nature apart from God’s grace.

For example, Christ said to the apostles in the Garden of Gethsemane, “Watch and pray that you may not enter into temptation; the spirit indeed is willing, but the flesh is weak” (Mk 14:38). According to Paul, if we are in “the flesh,” we are “hostile to God” and “cannot please God” (cf. Rom 8:1-14). In First Corinthians 2:14, he tells us, “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.” In First Corinthians 3:1, Paul goes on, “But I, brethren, could not address you as spiritual men, but as men of the flesh, as babes in Christ.” It requires supernatural grace in the life of the believer to believe the radical declaration of Christ concerning the Eucharist. As Jesus himself said both before and after this “hard saying”: “No one can come to me unless the Father who sent me draws him” (Jn 6:44, cf. 6:65). Belief in the Eucharist is a gift of grace. The natural mind—or the one who is in “the flesh”—will never be able to understand this great Christian truth.

3) On another level very closely related to our last point, Christ said, “It is the spirit that gives life, the flesh is of no avail,” because he wills to eliminate any possibility of a sort of crass literalism that would reduce his words to a cannibalistic understanding. It is the Holy Spirit that will accomplish the miracle of Christ being able to ascend into heaven bodily while being able simultaneously to distribute his body and blood in the Eucharist for the life of the world. A human body, even a perfect one, apart from the power of the Spirit could not accomplish this.

4) That which is spiritual does not necessarily equate to that which has no material substance. It often means that which is dominated or controlled by the Spirit.

One thing we do not want to do as Christians is to fall into the trap of believing that because Christ says his words are “spirit and life,” or “spiritual,” they cannot involve the material. When speaking of the resurrection of the body, Paul wrote: “It is sown a physical body, it is raised a spiritual body” (1 Cor 15:44). Does this mean we will not have a physical body in the resurrection? Of course not. In Luke 24:39, Jesus made that clear after his own Resurrection: “See my hands and my feet, that it is I myself; handle me, and see; for a spirit has not flesh and bones as you see that I have.”

The resurrected body is spiritual, and indeed we can be called spiritual as Christians inasmuch as we are controlled by the Spirit of God. Spiritual in no way means void of the material. That interpretation is more gnostic than Christian. The confusion here is most often based upon confusion between spirit—a noun—and the adjective spiritual. When spirit is used, e.g., “God is spirit” in John 4:24, it is then referring to that which is not material. However, the adjective spiritual is not necessarily referring to the absence of the material; rather, it is referring to the material controlled by the Spirit.

Thus, we could conclude that Jesus’ words, “It is the spirit that gives life, the flesh is of no avail” have essentially a twofold meaning. Only the Spirit can accomplish the miracle of the Eucharist, and only the Spirit can empower us to believe the miracle.

Note: Catholic Answers never recognized that Jesus Christ was eliminating the free food false followers in John chapter 6.