The Eucharist

SOURCE: THE ORTHODOX STUDY BIBLE
John 6:53-58
the 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 drink 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 lining Father sent Me, and I live becouse of the Father, so he who feeds on Me will live becouse of Me."
"This is the bread wich came down from heavan - not as your fathers ate the manna, and are dead. He who eats this bread will live forever."
6:53 Christ's body was crucified and His blood shed on the Cross. We receive the benefits of Christ's sacrifice by comming to Him in faith(.v35), and by communion with Him: we eat His flesh and drink His blood. These words refer directly to the Eurcharist, the mystery of Christ our life, we must partake of His eucharistic flesh and blood. St. John Chrysostom(Homily 47:7) teaches we must not understand the sacrament carnally, that is, according to the laws of physical nature, but spiritually (v.63), perceiving a true but mystical presence of Christ in the Eucharist.
6:54,55 St. Hilary of Poitier writes, "What we say concerning the reality of Christ's nature within us would be foolish and impious were we not tought by His very words...There is no room left for doubt about the reality of His flesh and blood, becouse we have both the witness of His words and our own faith. Thus, when we eat and drink these elemonts we are in Christ and Christ is in us" (On the Trinity, Book VIII, 14).
This reality, however, is a profound mystery of faith and drace. Orthodox theology teaches that in the Eucharist we partake not simply of the physical/material, but of the deified and glorified Body and Blood of Christ wich gives resurrection life.