Brothers and sisters, since the loaf of bread that we break is one, we, though many, are one body for we all partake of the one loaf. The Church observes today the Solemnity of the Most Holy Body and Blood of Christ (Corpus Christi). It is a feast that celebrates in a special way the sacrament of the Eucharist as THE sacrament of the Church. It is a feast whose significance in the life of the Church cannot be emphasized enough, for although Christ continues to be present in, and to the Church in many different ways, his presence in the sacrament of the Holy Eucharist is unique. For in the species of bread and wine (which after the words of consecration are transformed into the body and blood of Christ), Christ remains present in, and to the Church in a very tangible way (referred to as real presence). In the sacrament of the Holy Eucharist, not only are the faithful able to 'touch' Christ as if he were physically present to them, but Christ also gives himself as food to them. The Holy Eucharist, in other words, is a sacrament through which the mystery of the great event of the Incarnation continues to be felt. 
The sacrament of the Holy Eucharist assumes such a central place in the life of the Church because it is at the heart of the greatest prayer that the Church offers (Mass). As a matter of fact, it can be said that the Holy Eucharist is the very heart of the Mass since it is around its table that the Church gathers for her greatest prayer. All the other components of the Mass point towards the table of the Holy Eucharist. Moreover, as St. Paul reminds us in his letter to the Corinthians, the Holy Eucharist is a sacrament that we celebrate in obedience to the command of Christ because it is tied to the redemptive work that he accomplished (cf. I Corinthians 11:23-26). The sacrament of the Holy Eucharist, then, is both a memorial of Jesus’ self-offering on behalf of his brothers and sisters as well as his invitation to them to join him in his self-offering (do this in memory of me). 
Although it is the sacrament of the Holy Eucharist that is readily conjured in one’s mind whenever we speak of the Body of Christ, today’s feast celebrates more than the sacrament of the Eucharist since the Eucharist itself as a sacrament points to a deeper reality that transcends it. It goes without question that when Jesus instituted the Eucharist on the evening of the Last Supper, he associated the elements of bread and wine with his body which was soon to be offered for the salvation of the world (cf. Mark 14:22-24). But we also know from St. Paul that the Church in her members make up the body of Christ (cf. 1 Corinthians 6:15; Ephesians 1:22-23, 5:30). And since Christ lives in the members of his body (cf. John 15:4), the Church becomes part of that deeper and living reality to which the sacrament of the Eucharist points. As the body of Christ, the Church is therefore part of the real presence of Christ and as such she (the Church) must approach today's feast as a celebration of her very identity. It is this identity of the Church as the body of Christ that we hear St. Paul talking about in the Second Reading. 
Even though it was St. Paul himself who had evangelized the Corinthians, the cosmopolitan nature of this community was proving to be quite a challenge when it came to living out one's Christian identity. Being a port city, Corinth was home to a number of different religious expressions, the notable of which was sacrificial offering. While sacrificial offering was a non-issue for Christians, the challenge arose when it came to the purchasing and consumption of the meat which had been offered to idols. Christians with strong consciences had no problem with buying such meat (they argued that idols did not exist anyway). But their reasoning proved to be scandalous for those Christians who had weak consciences, who believed that the fact that the meats had been sacrificed to idols rendered them sacrilegious and unfit for consumption by Christians. It was a hot issue that was causing division in the community and Paul had to address it. The two verses that make up the Second Reading was part of Paul's attempt to address the issue.
In his address, Paul reminds the community about the exclusive and communal nature of the Christian faith. At baptism, one is baptized into a community of believers. He/she becomes part of that community so much so that what affects a member of the community affects the entire community. Through their baptism and participation in the Eucharistic meal, the members of the community had made themselves into a single organism. But most importantly, the sacrificial nature of the Eucharistic meal in which they participated called upon them to seek out the good of the other.  'The blood of Christ that we bless was poured for us, and the body of Christ of which we partake was broken for us,' Paul tells them,  'It is only right, therefore, that we too be poured and broken for our brothers and sisters if we have indeed become what we have consumed.' 
The belief in the real presence of Christ is tied to his dwelling in his disciples, the members of his body. This real presence is validated in the way the members of his body live their lives. For Jesus' real presence can only be said to be there when qualities of Jesus can be discerned in the community. The Holy Eucharist is indeed a great sacrament and indispensable for the Church. For it is in the Eucharist that Jesus continues to give himself for us as food and source of nourishment. But it is in the members of Christ's body, the Church, where forgiveness, humility, kindness, selflessness, and love can reside. It is in the Church that Christ is  really present. And it is this  real presence that we celebrate today.