It can doubtlessly be said that the central sacrament of the Church is Holy Eucharist. It is the sacrament of sacraments. It was established by Christ Himself: "When it was evening," Jesus "took bread, and blessed, and broke it, and gave it to the disciples and said, `Take, eat; this is My body, broken on behalf of all for the forgiveness of sins,' and "He took the cup, and when He had given thanks He gave it to them, saying, `Drink of it, all of you; for this is My blood of the New Covenant, which is shed for many for the forgiveness of sins.'" Christ added, "Do this in remembrance of Me" (Matthew, 26:20-9; Mark, 14:17-25; Luke, 22:14-38; John, 6:27-69; 1 Corinthians, 11:23-26).
From these words of Christ we see that the Holy Eucharist is truly the body and blood of Christ. It is not a symbol. It is truly the body and truly the blood of Christ. Christ did not say that "this symbolizes My body" and "this symbolizes My blood." He said, "this is My body" and "this is My blood." Of course, even after the celebration of the Holy Eucharist, all we see with our human eyes is bread and wine. Even the taste on our tongues is that of bread and wine. In reality and in essence, though, that which we see and that which we taste is truly the body and blood of Christ. How does this happen? How does this change occur? No one can say. It is done in a mysterious way with the intervention of the Holy Spirit. As the celebrant says: "And make this bread the precious Body of Your Christ, and that which is in this cup the precious Blood of Your Christ."
Therefore, from the above words of Christ we see that this sacrament was established by Christ "for the forgiveness of sins." The main purpose of the sacrament then is the forgiveness of man's sins. Along with the forgiveness, though, come the sanctification and glory, eternal life. This is why when the celebrant gives Holy Communion, he says to each person: "the Body and Blood of Christ, for the forgiveness of your sins and life eternal."
Even from the words of Christ it appears that this sacrament of Holy Eucharist is preeminently the sealing of the New Covenant between God and man. It is the testament of reconciliation and friendship.
Beyond the above statements, the very words of Christ reveal that this sacrament has to be repeated "in remembrance" of Christ, of His incarnation, sacrifice on the cross, burial, resurrection, and of His ascension into Heaven to be seated at the right hand of the Father, and His second glorious coming.
In other places in Holy Scripture, Christ has assured us that His Body is "truly food" and His Blood is "truly drink." Moreover, this is shown by the fearsome saying that "whoever does not eat My body and does not drink My blood, has no life in him." This proves that the Holy Eucharist is the spiritual nourishment of man. Just as man cannot live without natural nourishment, so neither can he live without spiritual nourishment--the body and blood of Christ--without Holy Eucharist. Christ makes this very clear. He says that "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" (John, 6:53-54).
Holy Eucharist unites man with God. It deifies him. Since man unites with God, he also unites with other people. St. Paul says that "because there is one bread, we who are many are one body, for we all partake of the One Bread" (1 Corinthians, 10:17). This unifying of the people among themselves into one body is like the unity of the three Persons of the Holy Trinity, Father, Son, and Holy Spirit.
We could say that the fruits of Holy Eucharist are the following: forgiveness of sins, cleansing, sanctification, justification, unity with God and with each other, spirituality, eternal life, glory, theosis.
In order for man to have all the fruits and benefits of the Holy Eucharist, he needs first to partake of it often. How often? Every time he attends the Divine Liturgy; and secondly, he needs to "approach with the fear of God, faith, and with love." In other words, to approach worthily, with reverence and faith in God, and with total love towards God and man.
Holy Eucharist is celebrated in the Church, but it can be celebrated in an open space or anywhere for that matter in times of necessity. It can be celebrated once per day. It is performed during the Divine Liturgy. Bread and wine are offered. This bread and wine are sanctified and, though they are physical substances, through the intervention of the Holy Spirit they are transformed into spiritual things--into the body and blood of Christ. God created, out of nothing, the visible (physical) and invisible (spiritual) world. From physical things--bread and wine--He makes the body and blood of Christ.
O God, how much amazement and delight we receive from Your great deeds. Your deeds are unfathomable, and Your wonders are incomprehensible. The way of our salvation is impossible for our limited minds to understand. I gaze with wonder and fear at the mystery of mysteries, the Holy Eucharist. We approach with faith and with love, yet we are unworthy. Make us worthy of this great gift. Do not allow us to partake "in judgment or condemnation" but for cleansing and sanctification, for forgiveness of sins, for glory and holy communion, and for life eternal. We thank You. O Lord, "Abide in us."