When we refer to the body of Christ, there are at least three different senses in which we use the phrase.
The first, of course, refers to the body which was crucified for us, was raised in the power of the Spirit, and which ascended into heaven. That body is the body of a true human being, and the one whose body it is has been given true dominion over all things in heaven and earth. He sits at the right hand of God the Father.
The second sense is the sacramental body—the bread before us, and the wine in the cup. This is my body, Jesus said. There have been more disputes about this than there ought to have been, but one thing we can say for sure. No Christian will say that the bread and wine are in no sense the body of Christ. When we eat and drink, we are partaking of Him.
The third sense refers to the Christian church. You are the body of Christ. There is one loaf, Paul says, one body, and he is talking about the congregation of the Lord.
But we should not be content with lining these three definitions up, putting them on a shelf in our minds. There is a mystery here, and the mystery concerns how the three definitions intertwine. When you eat a small bit of bread in faith, and drink the wine, you are being knit together with all your brothers and sisters, both here and around the world. When you are knit together with them, we are all growing up into a perfect humanity, as Paul says. We are being formed into a bride, without spot or wrinkle or any other blemish. And when that is completed, the bride will be given to the bridegroom and will become bone of His bone, flesh of His flesh—one body.
These things are way beyond us, and we ought not to despair over it because even the great apostle described it all as a great mystery. But God has created the world in such a way that disparate things may indwell one another—men and women, bread and wine, and the Lord in heaven.