"We must not objectivize God's presence, God's giving of himself to us in the eucharist, as just another of the many ways of being present to us. The eucharist is the centre of all other presences of God toward us. In the eucharist, we touch the basis of all reality, the Holy Trinity; here are concentrated the uncreated, personalized, loving energies of God as loving community. God's fullness of love moves toward us in order to transform us into his loving children."
––(George A. Maloney*, SJ, Be Filled with the Fullness of God [Hyde Park, New York: St. Paul's, 1993], p. 120).
* Fr. Maloney, God have mercy on his soul, was dual-rite Jesuit in the Russian Byzantine rite, was immersed in the teaching of the Eastern Fathers, and founded the John XXIII Institute for Eastern Christian Studies at Fordham University.
"Therefore, in order that we may become his Body, not in desire only, but also in very fact, let us become commingled with that Body. This, in truth, takes place by means of the food which he has given us as a gift, because he desired to prove the love which he has for us. It is for this reason that he has shared himself with us and has brought his Body down to our level, namely, that we might be one with him as the body is joined with the head. And to show the love he has for us he has made it possible for those who desire, not merely to look upon him, but even to touch him and to consume him and to fix their teeth in his Flesh and to be commingled with him; in short, to fulfill all their love. Let us, then, come back from that table like lions breathing out fire, thus becoming terrifying to the Devil and remaining mindful of our Head and of the love which he has shown us."
–– (quotation from St. John Chrysostom, Homilies on St. John's Gospel, as cited in Fathers of the Church [New York: Fathers of the Church, Inc., 1957], p. 33:468–469, as cited in G. Maloney, ibid., p. 125–126)
"I receive in Communion / the Body divinized as being that of God. / I too become god / in this inexpressible union. / See what a mystery! / The soul then and the body… / are one being in two essences. / Therefore these are one and two / in communion with Christ / and drinking his blood, / they are united to two essences, / united in this way to the essences of my God, / they become god by participation. / They are called the same name as that of him / in whom they have participated on a level of essence. / They say that coal is fire / and the iron is black. / Yet when the iron is immersed in the fire / it appears are fire. / If it then appears as such, / we also call it by that name.
[Fr. Maloney adds:] " We are received into the only-begotten Son of God by an ontological union, a unique oneness with God. Marriage perhaps comes closest to describing such a union and yet even that fails to express the oneness of person, Trinity and ourselves individually and all of us together united in the eucharist."
–– (quotation from Symeon the New Theologian, Hymns, 30.169–170, as cited in ibid., p. 131)
"[T]he whole of the ascetic and mystical life is a deepening and realization of our Eucharistic union with Christ the Saviour. … This means that the earliest childhood memories of the Church that an Orthodox Christian has will probably be linked with coming to receive Christ's Body and Blood; and the last conscious action of his life, so he hopes, will also be the reception of the Divine Gifts. So his experience of Holy Communion extends over the whole range of his conscious life. It is above all through Communion that the Christian is made one with and in Christ, 'christified', 'ingodded' or 'deified'; it is above all through Communion that he receives the firstfruits of eternity. … '[So perfect is this Mystery, so far does it excel every other sacred rite that it leads to the very summit of good things.] All human striving reaches here its ultimate goal[. … Wherefore the Eucharist, alone of sacred rites, supplies perfection to the other Mysteries]', says Nicolas Cabasilas. 'For in this sacrament we attain God himself, and God himself is made one with us in the most perfect of all possible unions…. This is the final mystery: beyond this it is not possible to go, nor can anything be added to it. … [After the Eucharist then, there is nowhere further to go. There we must stand, and try to examine the means by which we may preserve the treasure to the end.]'"
–– (Kallistos Ware, The Orthodox Way [Crestwood, NY: SVS Press, 1995], as citing Cabasilas, The Life in Christ [Crestwood, NY: SVS Press, 1974], pp. 114, 116, with some additions by myself from that work).
"[F] the early Fathers it [i.e., 'Eucharist‘] was the key word giving unity and meaning to all the 'elements' of the liturgy. … Eucharist (thanksgiving) is the state of perfect man. Eucharist is the life of paradise. Eucharist is the only full and real response of man to God's creation, redemption and gift of heaven. But this perfect man who stands before God is Christ. In Him alone all that God has given man was fulfilled and brought back to heaven. He alone is the perfect Eucharistic Being. He is the Eucharist of the world. In and through the Eucharist the whole creation becomes what it always was to be and yet failed to be. … The Eucharist of Christ and Christ the Eucharist is the 'breakthrough' that brings us to the table in the Kingdom, raises us to heaven, and makes us partakers of the divine food. For eucharist––thanksgiving and praise––is the very form and content of the new life that God granted us when in Christ He reconciled us with Himself. The reconciliation, the forgiveness, the power of life––all this has its purpose and fulfillment in this new state of being, this new style of life which is Eucharist, the only real life of creation with God and in God, the only true relationship between God and the world."
–– (Alexander Schmemann, For the Life of the World [Crestwood, NY: SVS Press, 1973], pp. 34, 37–39).
"After the transformation of the bread and wine in the Mystery of the Eucharist into the Body and Blood, they no longer return to their former nature, but remain the Body and Blood of the Lord forever, whether or not they are consumed by the faithful. … Since to the God man Christ it is fitting to offer a single inseparable Divine worship, both according to His Divinity and His humanity, as a consequence of their inseparable union, therefore also to the Holy Mysteries of the Eucharist there should be given the same honor and worship which we are obliged to give to the Lord Jesus Christ Himself. … To receive communion of the Body and Blood of the Lord is the essential, necessary, saving, and consoling obligation of every Christian. … The saving fruits or effects of the Mystery of the Eucharist, if only we communicate them worthily, are the following: It unites us in the most intimate fashion with the Lord…." Etc.
–– (Protopresbyter Michael Pomazansky, Orthodox Dogmatic Theology, chap. 8).