In context, Jesus was saying that the "bread" that the people must eat is their BELIEF, and NOT actual physical bread that you ingest.

No it doesn’t. That is your interpretation. We know it is the case that Jesus’ flesh was supposed to be eaten because some Jews took issue with this and left Jesus over this teaching.

When it comes to the famous “Bread of Life” discourse in chapter six of the Gospel of John, Catholics often argue that Jesus meant his words “eat my flesh” and “drink my blood” literally. This is in large part because he didn’t backtrack when confronted with the suspicions of either the Jews (“How can this man give us his flesh to eat?”—6:53) or his disciples (“This is a hard saying, who can listen to it?”—v. 60).

But some Protestants counter that Jesus did clarify his meaning in John 6, and he did so in verse 63: “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.” Protestant apologist Matt Slick, founder of Christian Apologetics and Research Ministry, interprets this text as Jesus “stating that the words he was speaking were spiritual words when talking about eating his flesh and drinking his blood.” Slick concludes, “[Jesus] did not say they were literal words; that is, he did not say that they were his actual body and blood.”

Slick seems to be arguing that Jesus’ words were intended to be interpreted in a spiritual sense—that’s to say, his words were intended to have a spiritual meaning and not that his words refer to his actual body and blood.

Let’s take a look at how we might respond and see whether we as Catholics need to abandon the above line of reasoning in support of our belief.

One problem with Slick’s argument is that it doesn’t explain why Jesus’ disciples still leave him. The disciples leave Jesus immediately after he gives the “spirit and life” teaching (v. 66). Why would the disciples still leave Jesus if Jesus were clarifying that he intended his words to have only a spiritual meaning?

The whole point of interpreting his words as having merely a spiritual meaning is to suggest that his command to eat his flesh and drink his blood is not that difficult a teaching. The difficulty, therefore, seemingly would have disappeared for the disciples after this supposed clarification, and they would have thereby stayed with Jesus. But that’s not what happened.

Now, Slick, or another Protestant, might reply, “The remaining difficulty was accepting Jesus’ divine claim to have the power to give eternal life.” But the disciples were “disciples,” which means they were already predisposed to accept such a claim, assuming they weren’t already believing in Jesus’ divinity, but only in his messiahship.

Furthermore, elsewhere in John’s Gospel where Jesus makes divine claims (8:58, 10:30-33), his disciples never leave him. It’s “the Jews” who oppose him and try to kill him (John 8:59, 10:33). So it would seem that Jesus’ disciples leave him in John 6 not for divine claims, but for the reason of the difficulty of his command to eat his flesh and drink his blood.

Slick’s counter-argument also fails because it doesn’t consider Jesus’ statement about “the flesh,” which he contrasts with “the Spirit”: “It is the Spirit that gives life, the flesh is of no avail” (v. 64). Understanding the idiom of “the flesh” sheds light on what Jesus meant by his statement, “my words are spirit and life.”

“The flesh” is a New Testament expression that often describes human nature apart from God’s grace (Rom. 8:1-14), as well as those who see reality only from an earthly perspective. John uses the expression this way in John 8:15, where Jesus says to the Pharisees, “You judge according to the flesh [Gk. ho sarx].”

So when we come back to John 6:63, and Jesus says, “The flesh is of no avail,” Jesus means that his teaching can’t be analyzed from an earthly perspective. The eyes of faith are needed, since eating his flesh and drinking his blood is going to involve the miraculous, like his ascension into heaven, which Jesus appeals to in response to the disciples’ difficulty with his command to eat his flesh and drink his blood (vv. 60-61).

The need for faith is the reason why Jesus puts these commands within the bookends of his teaching: “No one can come to me unless the Father who sent me draws him” (v. 44) and “no one can come to me unless it is granted him by the Father (v. 65). It’s not that his exhortation to “eat” and “drink” have only a spiritual meaning, but rather that his words are discerned, not in a worldly or world-focused way.

The Catholic Encyclopedia sums up this explanation nicely:

In the scriptural opposition of “flesh and blood” to “spirit,” the former always signifies carnal-mindedness, the latter mental perception illumined by faith, so that it was the intention of Jesus in this passage to give prominence to the fact that the sublime mystery of the Eucharist can be grasped in the light of supernatural faith alone, whereas it cannot be understood by the carnal-minded, who are weighed down under the burden of sin.

The argument that Jesus is clarifying his disciples’ literal understanding and helping them with their difficulties by saying his words are “spirit and life” doesn’t hold water when critically examined. A Catholic, therefore, doesn’t need to give up on the argument that appeals to Jesus’ doubling down in the face of the interior objections of both the Jews and his disciples.