In 1 Corinthians 12:12-20 Paul talks about our human body having many members and how all the body members, though many, are one body. Then Paul says, so it is with Christ. For in one Spirit, we were all baptized into one body. God arranged the members in the body, each as He chose.

If all were a single member, where would the body be? As it is, there are many parts, yet one body. Now, while all Christians make up the body of Christ, each Christian has a unique function to fill as part of that one body.