St Augustine helps us to understand the dynamic of Eucharistic communion when he mentions a sort of vision that he had, in which Jesus said to him: “I am the food of strong men; grow and you shall feed on me; nor shall you change me, like the food of your flesh into yourself, but you shall be changed into my likeness” (Confessions, VII, 10, 18).
Therefore whereas food for the body is assimilated by our organism and contributes to nourishing it, in the case of the Eucharist it is a different Bread: it is not we who assimilate it but it assimilates us in itself, so that we become conformed to Jesus Christ, a member of his Body, one with him. This passage is crucial. In fact, precisely because it is Christ who, in Eucharistic communion changes us into him, our individuality, in this encounter, is opened, liberated from its egocentrism and inserted into the Person of Jesus who in his turn is immersed in Trinitarian communion. The Eucharist, therefore, while it unites us to Christ also opens us to others, makes us members of one another: we are no longer divided but one in him. Eucharistic communion not only unites me to the person I have beside me and with whom I may not even be on good terms, but also to our distant brethren in every part of the world.
There is nothing magic about Christianity. There are no short-cuts; everything passes through the humble and patient logic of the grain of wheat that broke open to give life, the logic of faith that moves mountains with the gentle power of God. For this reason God wishes to continue to renew humanity, history and the cosmos through this chain of transformations, of which the Eucharist is the sacrament. […]
Let us walk with no illusions, with no utopian ideologies, on the highways of the world bearing within us the Body of the Lord, like the Virgin Mary in the mystery of the Visitation. With the humility of knowing that we are merely grains of wheat, let us preserve the firm certainty that the love of God, incarnate in Christ, is stronger than evil, violence and death. We know that God prepares for all men and women new heavens and a new earth, in which peace and justice reign - and in faith we perceive the new world which is our true homeland.
Benedict XVI, Homily, Solemnity of Corpus Christi, 23 June 2011