In the Eucharist, we become partakers of the divine nature, Christ-bearers.
The Eucharist is the efficacious sign and sublime cause of that communion in the divine life and that unity of the People of God by which the Church is kept in being. (Catechism, 1325)
[St. Cyril of Jerusalem, Mystagogic Catechesis, 3:] Therefore, with all confidence we receive this as the Body and Blood of Christ. For in the type of bread the Body is given to you, and in the type of wine, the Blood is given to you, so that, partaking of the Body and Blood of Christ, you may become one Body and one Blood with Christ. And so, we become Christ-bearers, when his Body and his Blood have been diffused in our members. Thus, according to the Blessed Peter, we become “partakers of the Divine Nature” (2 Pet 1:4), (The Hidden Manna, James O’Connor, 28)
Man is divinized in likeness through grace and love.
The principal end of the Incarnation is to give us an incomparable, inconceivable gift, which is to share in God’s own divine nature through incorporation into Christ’s Mystical Body. The Fathers of the Church frequently formulate this in the startling statement that God became man, so that man could be divinized and come to share in the divine nature.
This divinization of man does not mean that man takes the place of God. God cannot lose his throne or his divine Majesty. On the contrary, the divinization of man is the transformation of man into the full image and likeness of God through the gift of sanctifying grace and supernatural charity.
Through grace we are given a participation in the divine nature, as St Peter states in his second letter, 1:4, “that you may be made partakers of the divine nature.” Through sanctifying grace and charity, we are given a share in the inner life of God himself. (Eucharist, Feingold, 20)
Our divinization is a divine interchange.
The Fathers of the Church love to describe this divinization of man through the Incarnation of the Son of God as a kind of divine interchange or commerce, by which the God of majesty takes on the condition of frail mortal man in order to clothe man in the divine garments of sanctifying grace and supernatural charity, and bring him to the beatific vision of God in heaven. This interchange is explained in a homily of Saint Augustine:
It was not enough for our God to promise us divinity in himself, unless he also took on our infirmity, as though to say, “Do you want to know how much I love you, how certain you ought to be that I am going to give you my divine reality? I took to myself your mortal reality.” The Son of God became a son of man, in order to make sons of men into sons of God. For the maker of man was made man, so that man might be made a receiver of God. (Eucharist, Feingold, 21)
Eucharist divinizes man.
The Eucharist is intimately connected with this primary end of the Incarnation. The divinization of man and the giving of sanctifying grace by incorporating us in His Mystical Body. (Eucharist, Feingold, 23)
The divine life of God within us.
About the truth of his Flesh and Blood there is left no room for doubt. For by the Lord’s own words and by our faith [we know] that it is truly flesh and truly blood. And when we have received and drunk these realities it comes about that we are in Christ and Christ is in us. Is this not the truth? Let it happen that those who deny that Christ is God deny this also. He is in us through his Flesh, and we are in him, and that by which we are with him is in God. (St. Hilary of Poitiers, De Trinitate; Adoration, Guernsey, 46)
Christ’s humanity brings us into His divine life.
In the Eucharist, Christ gives us His humanity to be our nourishment, so that our humanity, receiving His, may be nourished by His divinity. Christ’s humanity, made substantially present in the Eucharist, is the perfect bridge by which to give us a progressive share in His divinity. (Eucharist, Feingold, 24)
The Eucharist brings us a share in God’s divine life.
The God who was manifested mingled himself with the nature that was doomed to death, in order that by communion with the divinity, human nature may be deified together with him. It is for this purpose that by the divine plan of his grace, he plants himself in believers by means of that flesh, composed of bread and wine, blending himself with the bodies of believers, so that man also may share in immortality by union with the immortal. (St. Gregory of Nyssa, Oratio Catechetica, 37; Adoration, Guernsey, 49)
Christ dignifies man in Communion
If the Incarnation reveals man’s dignity because “the Son of God has united Himself in some fashion with every man,” how much more true that is by the institution of the Eucharist! For in Holy Communion we receive His very self into ourselves so that we may be assimilated into Him. (Eucharist, Feingold, 26)
The Eucharist is the heart of the New Covenant: He brings us into His intimate union and divine life.
By giving us Communion, the Eucharist brings us into the most intimate union with Jesus and causes our divinization, and it also makes it possible for us to offer the most perfect worship of God by giving us the means to offer ourselves to the Father in union with Christ’s own sacrifice. The Eucharist, therefore, is the heart of the New Covenant. (Eucharist, Feingold, 36)
Partakers of the divine life; the Kingdom of God on earth
Those who feed on Christ in the Eucharist need not wait until the hereafter to receive eternal life: they already possess it on earth, as the first-fruits of a future fullness which will embrace man in his totality. For in the Eucharist we also receive the pledge of our bodily resurrection at the end of the world: “He who eats my flesh and drinks my blood has eternal life, and I will raise him up at the last day” (Jn 6:54). (18, Ecclesia De Eucharistia, PJPII)
The Eucharist intensifies God’s Indwelling.
Or as Jesus says in John 6:56-57: “He who eats my flesh and drinks my blood abides in me, and I in him. As the living Father sent me and I live because of the Father, so he who eats me will live because of me.” In other words, the proper effect of the Eucharist is the intensifying of the indwelling of Christ in the soul and of the soul in Christ. And where Christ indwells, there also are the Father and the Holy Spirit. (Eucharist, Feingold, 512)
The Holy Spirit changes the bread into Christ, but also deifies man.
The same Holy Spirit who upon the altar changes earthly bread into heavenly bread changes us from earthly men to heavenly, deified men. … [T]he Holy Spirit fuses us with Christ by His divine fire, not only morally, but…physically, so that we form one body with Him. …
[H]e brings about within our interior not only a moral conversion, …but an altogether real, physical assimilation and union with God. By the reception of grace, our soul takes on a higher nature; that is, with regard to its interior condition, its faculties, and its activity it is transformed into the image of the divine nature… (The Mysteries of Christianity, Scheeben, 502-3)
God raises us in our nature to live His life.
Eternal life, therefore, consists in knowing God as He knows Himself, and in loving Him as He loves Himself. But, if we penetrate more deeply into this matter, we see that this divine knowledge and love are possible only if God, so to speak deifies us in our very soul. … [W]e will be capable of a divine knowledge and of a supernatural love only if we have received a participation in the very nature of God, of the Deity; only if our soul, the principle of our intellect and will, has been in a sense, deified or transformed into God, as iron plunged into the fire is transformed, so to speak into fire, without ceasing to be iron. (Christian Perfection and Contemplation, Lagrange, 118-119)
Holiness is life in relation to the divine being, in the divine life.
To be holy,…means that he continually lives in relation to the divine being, “partakes in the divine nature” (2 Pet 1:4). to be immaculate means to be free from alienating factors that are incompatible with our essence, which is being in the image and likeness of God… (On Love, Ratzinger, 15)