John Calvin on 1 Corinthians 12:20

20. Many members — one body He repeats this the oftener, because the stress of the whole question lies here — that the unity of the body is of such a nature as cannot be maintained but by a diversity of members; and that, while the members differ from each other in offices and functions, it is in such a way as to have a mutual connection with each other for the preservation of the one body. Hence no body can retain its standing without a diversified symmetry of the members, that we may know to consult public as well as private advantage, by discharging, every one, the duty of his own station.