Certainly the Eucharist is food for the believer if one is to believe Jesus’ in His colloquy at Capernaum. It is food for endurance till eternal life. It provides the grace necessary to complete the race. Jesus compares it to the manna that was eaten in the desert to sustain the Israelites. But Jesus is speaking of the New Covenant requiring a new sustenance which is His Body and Blood. In making this comparison He says that real bread comes from the father just as He and then says that He is the bread of life. If one eats this bread they will live forever. The disciples listening to Him began to realize that Jesus was not speaking metaphorically but literally and then we come to the following verse:
(Joh 6:52 DRB) (6:53) The Jews therefore strove among themselves, saying: How can this man give us his flesh to eat
Then Jesus said in unambiguous literal language:
(Joh 6:53 DRB) (6:54) Then Jesus said to them: Amen, amen, I say unto you: except you eat the flesh of the Son of man and drink his blood, you shall not have life in you.
The following verse indicates the purpose of eating His body and drinking His blood. It is so that we can “abidete” or in other words remains in Him by the Grace bestowed by the act of receiving His Body and His Blood. But the Eucharist benefits us even more in that it augments our union with Christ as the principal fruit of receiving the Eucharist is an intimate union with Christ.
(Joh 6:56 DRB) (6:57) He that eateth my flesh and drinketh my blood abideth in me: and I in him.
An additional benefit of the Eucharist is that it is impossible to unite to Christ without the cleansing of past sins and preserving us from future sins through His grace. This is part of the sanctification process where we grow in our faith in him which separates us further from the risk of mortal sin. Additionally, the Eucharist participation renews, strengthens and deepens ones incorporation into the Church which is achieved through Baptism. It joins us to the entire Church Militant, Suffering and Triumphant.
This is what St. Ignatius said about the Eucharist at the end of the first century, “ the one bread that provides the medicine of immortality, the antidote for death, and the food that makes live forever in Jesus Christ.”
One may ask the question does God’s spiritual work always require a physical channel. “Always” is a very dangerous position to take when speaking of God as God can as our sovereign creator do things however he wishes. So this is really not a matter of “always” but instead, did God use the physical channel of Jesus transforming simple bread and wine into His body and Blood to bestow the Grace of eternal life.
I was reading another apologist’s commentary some time ago and He related how some Protestants get an almost Docetist view when it comes to the Eucharist. They have no problem believing something to be spiritual but when it comes to mixing spirit and matter they seem to experience intellectual and theological mind block. This is the usual excuse for not believing in Sacraments because a spiritual reality is being conveyed by means of matter. They may even believe that this is a violation of the divine plan. Matter instead of being used is to be avoided which would explain why some have difficulties understanding the incarnation. Many believe that it would be much easier if God did not dirty himself with matter. The Eucharist proves that God loves matter because He comes to us under the appearance of bread and wine. In doing so there is no contradiction in Christ being physically and Sacramentally present.
One may question how can Christ be present in the Eucharist and be also in heaven and that is a fair question. First of all, in my explanation let me make it clear that how Christ performs this miracle is a great mystery that we accept on faith through our spirit to His. If we look at the account of the last supper we see Jesus present in two ways. He is present at the table in a natural way and is present also in a sacramental way which is no different than the Eucharistic experience today and through the history of the Church. How this is done while being a mystery is not impossibility just because it cannot be understood fully with our reason. We can all accept as Christians that God is everywhere and that He is present in a spiritual sense when we are gathered together. This is no greater a mystery than him reigning in heaven in His glorified body and on earth in His natural body. If he can create the universe from nothing can he not make bread and wine into His Body and Blood? These things may be beyond our understanding but certainly not beyond God’s abilities.
For those who do not believe in the real presence there are the difficulties of the following verses:
(1Co 11:26 DRB) For as often as you shall eat this bread and drink the chalice, you shall shew the death of the Lord, until he come.
(1Co 11:27 DRB) Therefore, whosoever shall eat this bread, or drink the chalice of the Lord unworthily, shall be guilty of the body and of the blood of the Lord.
(1Co 11:28 DRB) But let a man prove himself: and so let him eat of that bread and drink of the chalice.
(1Co 11:29 DRB) For he that eateth and drinketh unworthily eateth and drinketh judgment to himself, not discerning the body of the Lord.
(1Co 11:30 DRB) Therefore are there many infirm and weak among you: and many sleep.
People who refuse to believe in the real presence believe that this represents a metaphor. But, if it is a mere metaphor, how can one be “guilty of the body and Blood” when one receives unworthily? As one scholar put it “Plain and simple reason seem to tell us that the presence of Christ’s body is necessary for an offense committed against it.” (Nicholas Cardinal Wiseman, Lectures on the Real Presence) It would seem reasonable that one cannot be guilty of Christ’s body and Blood if it is not present in the Sacrament. Other scholars said ” No one is guilty of homicide if he merely does damage to the statue or picture of a man without touching the man in person.” (Rumble and Carty, Eucharist Quizzes to a Street Preacher) The question might be asked in light of St. Paul’s teaching, can one be theologically satisfied in the meaningless belief in a Real Absence than the fuller meaning of a Real Presence.
"Jesus made it exceedingly obvious what He meant. John 6:63 declares, “The Spirit gives life; the flesh counts for nothing. The words I have spoken to you are spirit and they are life.” Jesus specifically stated that His words are “spirit.” "
He had just told the listeners to eat His Body and to drink His Blood. Is it reasonable to say then that He is contradicting His previous statement. No possible way that he was teaching so ambiguously.