"There are different kinds of gifts, but the same Spirit. There are different kinds of service, but the same Lord. There are different kinds of working, but the same God works all of them in all men....
"The body is a unit, though it is made up of many parts; and though all its parts are many, they form one body. So it is with Christ. For we were all baptized by one Spirit into the one body -- whether Jews or Greeks, slave or free -- and we were all given the one Spirit to drink.... (I Cor. 12:4-6, 12-13 NIV).
This classic passage of Paul's in I Corinthans lays out in careful detail the doctrine of the unity and diversity of the Church, described as Christ's body alive on the earth. He makes an analogy to the physical body, which has many parts but functions as a unit. The description is sufficient to make the relationship clear in practical life. In fact this presents an ideal of any social group: that it should have a structure with features of unity, diversity, and equality.