What does 1 Corinthians 10:17 mean?

Paul is describing the practice of Christian communion to build his case for why believers should not knowingly eat food that has been offered to pagan idols. He has written that by consuming the bread and wine, we are together participating in the body and blood of Jesus.

Now Paul shows how that creates a unity among believers. He points to the "one bread." The practice of the day would have been to start with a single loaf of bread and break off pieces to distribute to each person.

Paul is making the same connection in reverse. Christians are many different people who come together to form one body, which is Christ's body (1 Corinthians 12:27). This is a theme of Scripture which challenges mankind's natural tendency towards division (Galatians 3:28). Modern people take the equality of all people as a given, but prior to Christianity, it was a radical idea.

The loaf of bread, too, represents Christ's body, broken into pieces for us. What a beautiful double-picture of Christ's broken body and the whole body of Christ.