How does Paul use the human body in 1 Corinthians 12:12?
Paul uses the human body as an example: just as one physical body has many members yet remains one body, so also is Christ. Christ is the head, and the many members compose His body, showing that believers become members of Christ's body through the Spirit.
Les explains that in 1 Corinthians 12:12 Paul uses the human body as an example. The human body is one yet has many members, and all the members of that one body, though many, are still one body. Les illustrates this with eyes, hands, fingers, nerve endings, and the central nervous system: if you strike your thumb with a hammer, the whole body hurts, not just the thumb. Then Paul says, "So also is Christ." Christ is the head of the body, composed of many members. Les notes that some ridicule the idea of the body of Christ as an invisible entity, but Scripture teaches it, especially in Paul's writing: believers become members of the body of Christ, of which He is the head in heaven, while we are the body still here on earth. Les asks how we become a member of the body of Christ. You did not sign up for it, and no preacher baptized you into it; first you had to believe the gospel, and the Holy Spirit automatically, immediately, the moment we believe, as verse 13 says, "for by one Spirit."
For as the body is one, and hath many members, and all the members of that one body, being many, are one body: so also is Christ.