"this do in remembrance of me."
I found the best understanding of the Eucharist is by reading His Word and gleaning how He presented it.
Guys, do you suppose that +Ignatius of Antioch, disciple of the Apostle John, appointed Bishop of Antioch by +Peter and reputed by pious tradition to have been the child who sat on Christ's lap could have gotten it wrong when, in about 100 AD he wrote:
"They [i.e. the Gnostics] 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 Smyrneans 7:1)
As an Orthodox Christian I can't tell you the "how" of this, Aquinas notwithstanding, except to say that it happens by the power of the Holy Spirit. I can also tell you that The Church has always and everywhere believed in the Real Presence of Christ in the Eucharist.
I'm glad someone finally "understood" it and "got it right". ;O)
The Real Presence of Christ in the Eucharist
by Frank J. Sheed
The Blessed Eucharist is the Sacrament. Baptism exists for it, all the others are enriched by it. The whole being is nourished by it. It is precisely food, which explains why it is the one sacrament meant to be received daily. Without it, one petition in the Our Father-"Give us this day our daily bread"-lacks the fullness of its meaning.
Early in his ministry, as St. John tells us (ch 6), Our Lord gave the first promise of it. He had just worked what is probably the most famous of his miracles, the feeding of the five thousand. The next day, in the synagogue at Capernaum on the shore of the sea of Galilee, Our Lord made a speech which should be read and reread. Here we quote a few phrases: "I am the Bread of Life"; "I am the Living Bread, which came down from heaven. If any man eat of this bread, he shall live forever: and the bread that I will give, is my flesh for the life of the world"; "He that eats my flesh, and drinks my blood, has everlasting life: and I will raise him up in the last day. For my flesh is meat indeed: and my blood is drink indeed. He that eats my flesh, and drinks my blood, abides in me, and I in him"; "He that eats me shall live by me."
He saw that many of his own disciples were horrified at what he was saying. He went on: "It is the spirit that quickens: the flesh profits nothing." We know what he meant: in saying they must eat his flesh, he did not mean dead flesh but his body with the life in it, with the living soul in it. In some way he himself, living, was to be the food of their soul's life. Needless to say, all this meant nothing whatever to those who heard it first. For many, it was the end of discipleship. They simply left him, probably thinking that for a man to talk of giving them his flesh to eat was mere insanity. When he asked the Apostles if they would go too, Peter gave him one of the most moving answers in all man's history: "Lord, to whom shall we go?" He had not the faintest idea of what it all meant; but he had a total belief in the Master he had chosen and simply hoped that some day it would be made plain.
There is no hint that Our Lord ever raised the matter again until the Last Supper. Then his meaning was most marvellously made plain. What he said and did then is told us by Matthew, Mark, and Luke; and St. Paul tells it to the Corinthians (1 Cor 10 and 11). St. John, who gives the longest account of the Last Supper, does not mention the institution of the Blessed Eucharist; his Gospel was written perhaps thirty years after the others, to be read in a church which had been receiving Our Lord's body and blood for some sixty years. What he had provided is the account we have just been considering of Our Lord's first promise.
Here is St. Matthew's account of the establishment: "Jesus took bread, and blessed, and broke: and gave to his disciples, and said, Take ye and eat: This is my body. And taking the chalice he gave thanks: and gave to them, saying: Drink ye all of this. For this is my blood of the New Testament, which shall be shed for many unto remission of sins."
Since they deal with the food of our life, we must examine these words closely. What we are about to say of "This is my body" will do for "This is my blood" too. The word is need not detain us. There are those, bent upon escaping the plain meaning of the words used, who say that the phrase really means "This represents my body." It sounds very close to desperation! No competent speaker would ever talk like that, least of all Our Lord, least of all then. The word this, deserves a closer look. Had he said, "Here is my body," he might have meant that, in some mysterious way, his body was there as well as, along with, the bread which seems so plainly to be there. But he said, "This is my body"-this which I am holding, this which looks like bread but is not, this which was bread before I blessed it, this is now my body. Similarly this, which was wine, which still looks like wine, is not wine. It is now my blood.
Every life is nourished by its own kind-the body by material food, the intellect by mental food. But the life we are now concerned with is Christ living in us; the only possible food for it is Christ. So much is this so that in our own day you will scarcely find grace held to be Christ's life in us unless the Eucharist is held to be Christ himself.
What Our Lord was giving us was a union with himself closer than the Apostles had in the three years of their companionship, than Mary Magdalen had when she clung to him after his Resurrection. Two of St. Paul's phrases, from 1 Corinthians 11 and 10, are specially worth noting:
"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"; and "We, being many, are one bread, one body, all that partake of one bread"- a reminder that the Eucharist is not only for each man's soul but for the unity of the Mystical Body.
I can see why a Christian might be unable to bring himself to believe it, finding it beyond his power to accept the idea that a man can give us his flesh to eat. But why should anyone to escape the plain meaning of the words?
For the Catholic nothing could be simpler. Whether he understands or not, he feels safe with Peter in the assurance that he who said he would give us his body to eat had the words of eternal life. Return again to what he said. The bread is not changed into the whole Christ, but into his body; the wine is not changed into the whole Christ, but into his blood. But Christ lives, death has no more dominion over him. The bread becomes his body, but where his body is, there he is; the wine becomes his blood but is not thereby separated from his body, for that would mean death; where his blood is, he is. Where either body or blood is, there is Christ, body and blood, soul and divinity. That is the doctrine of the Real Presence.