For the body - The body is made up of many members, which have various offices. So it is in the church. We are to expect the same variety there; and we are not to presume either that all will be alike, or that any member that God has placed there will be useless.

For the body is not one member - The mystical body, the Church, as well as the natural body, is composed of many members.

(9) For the body is not one member, but many.
(9) He amplifies that which followed of the similitude, as if he should say, "The unity of the body is not prevented by this diversity of members, and furthermore it could not be a body if it did not consist of many members, and those being different."

For the body is not one member,.... Not only one; nor is anyone member the body, though ever so eminent, as the head or eye: thus the church of Christ is not one person only, or does not consist of one sort of persons; as only of Jews, or only of Gentiles, or only of rich and freemen, or only of men of extraordinary gifts and abilities, or greatly eminent for grace and spiritual knowledge:
but many; members, as the Arabic version adds; as eyes, ears, hands, feet, &c. so in the mystical body of Christ, the church, there are many members, some in a higher station, others in a lower; some of greater gifts, grace, and usefulness, others of lesser; some Jews, other Gentiles; some bond, others free; yet all one in Christ the head, and all related to each other.

Translate, "For the body also." The analogy of the body, not consisting exclusively of one, but of many members, illustrates the mutual dependence of the various members in the one body, the Church. The well-known fable of the belly and the other members, spoken by Menenius Agrippa, to the seceding commons [LIVY, 2.32], was probably before Paul's mind, stored as it was with classical literature.