The first step in correctly understanding any Scripture passage is to hear it within the context in which the sacred author originally placed it. Just as the individual actions of our lives make sense only against the background of our entire lives, so we can't take just a verse of two of Scripture out of the writer's work and think we're getting from those lines what the author originally put in them.
Nowhere have we "sinned" more against this biblical principle than in our understanding of the Eucharist. We zero in on Jesus' words of institution - "This is my body/blood" - and completely ignore the context in which our sacred writers have Jesus proclaim them. Through the centuries we've spent most of our theological time reflecting on how the bread is transformed into Jesus' body; the wine into his blood. Little time has been given to exploring the implications of the Eucharistic community's transformation into the body and blood of Christ. Yet that's almost always the context in which our Christian sacred authors place Jesus' words over the bread and wine.
Today's I Corinthians pericope provides the earliest scriptural reference to the Eucharist. Paul employs these two short verses to illustrate how ridiculous it is for Jesus' followers to live their faith as "independent contractors." Those who imitate Jesus have a responsibility to all others who also imitate Jesus. For the Apostle, the greatest and most practical sign of that unity is the community's participation in the Lord's Supper. There they most die and rise; there they are most one.
Every Corinthian Christian knows what Paul means when he asks, "The cup of blessing that we bless, is it not a participation in the blood of Christ? The bread that we break, is it not a participation in the body of Christ?" In this context Paul's not talking about our being part of the bread and wine. He's referring to our participation in the community as the blood and body of Christ. If he weren't, the next verse wouldn't make sense. "Because the loaf of bread is one, we, though many, are one body, for we all partake of the one loaf." Ironically, the vast majority of Catholic parishes don't follow Paul's directive. For them, the loaf isn't one. The Eucharist is confected in small, individual wafers. Paul's enemies would point to this practice and use it as an argument against his passion for Eucharistic unity.
Even John's classic words in today's gospel should never be taken out of the gospel context in which the evangelist places them. All of us have practically memorized the words, "If you do not eat the flesh of the Son of Man and drink his blood, you have no life in you." The evangelist here shines the spotlight on Jesus' bread/body, wine/blood, warning us about the lifeless existence of those who refuse to participate in consuming them. Yet during John's actual Last Supper narrative, Jesus emphasizes another dimension of the Eucharist, one many of commemorated on Holy Thursday – the foot washing. Scripture scholar Sister Sandra Schniders believes it's only in such "out of control" actions of service to others that we can actually build the body of Christ as Christ wishes it to be built. For John, the life-giving aspect of Jesus' body and blood can only correctly be appreciated when we consume his body and blood in the context of a life-giving community.
We now hear Moses' first reading words with a different understanding. "He fed you with manna . . . to show you that not by bread alone do we live, but by every word that comes forth from the mouth of Yahweh."
Those who concentrate solely on the Eucharistic bread and wine might be the very people with whom Moses, Paul, and John are struggling.