Sunday we will share in Holy Communion, with God and with each other.  We want you to partake together with discernment, understanding, faith and joy.  Toward that end, here is an excerpt from a Mike Horton article:
There are essentially 4 views of what happens in Holy Communion. First, there is the Roman Catholic view, which is familiar to many. The official teaching of the Roman Catholic Church is that the bread and wine are actually changed into the body and blood of Christ. This is called “transubstantiation,” from two words meaning, “to change substance.” The bread still looks like bread and the wine still has all of the appearances of wine, but appearances are deceiving. Furthermore, the Lord’s Supper, according to the Roman Catholic Church, is the repetition of Christ’s atoning sacrifice and every time one participates in this sacrament, they believe that Christ is being sacrificed again on the altar for their sins.

(Views 2,3, and 4) At the time of the Reformation, however, Protestants differed in their understanding of what actually was received–and how–in Holy Communion. First, the Anabaptists (View #2) interpreted this meal as merely a memorial or symbolic remembering of Christ’s death. The purpose was to arouse a sense of gratitude and duty in the light of the suffering Jesus endured for us. The Lutherans (View #3) argued that this denied Christ’s express statement, “This is my body,” and made this sacrament into the work of man, because the activity was human–my remembering, rather than divine–God forgiving. Lutherans believe, therefore, that Christ is physically present at the altar in this sacrament, but deny the Roman Catholic doctrine of a change in substance from bread and wine into body and blood. They also, of course, deny the notion of a resacrifice of Christ. The Reformed (View #4 and that of Christ Community), after Calvin, were influenced by the Eastern Orthodox interpretation, arguing, along with Lutherans and Roman Catholics, that Christ is truly communicated through this sacrament, against the Anabaptist view of Communion as a mere memorial. But they believed that the mode or means of receiving Christ was by the Holy Spirit uniting believers to Christ in heaven through the elements of bread and wine.

The apostle Paul says, in fact, that Holy Communion is an actual participation in the body and blood of Christ: “Is not the cup of thanksgiving…a participation in the blood of Christ? And is not the bread the we break a participation in the body of Christ?” “Therefore,” says Paul, “whoever eats the bread or drinks the cup of the Lord in an unworthy manner will be guilty of sinning against the memory of the body and blood of the Lord.” Is that it? No, Paul says that he “will be guilty of sinning against the body and blood of the Lord.”

But the purpose of this Holy Supper is not to hold out judgment, but rather to hold out God’s forgiveness and pardon. Through it, we receive the benefits of Christ’s death and present intercession; in fact, through it, we receive nothing less than Christ himself.

the article is HERE