John Calvin Commentary 1 Corinthians 12:15

"If the foot shall say, Because I am not the hand, I am not of the body; it is not therefore not of the body." — 1 Corinthians 12:15 (ASV)

This is a further elaboration (ἐπεξεργασία) of the preceding statement, or in other words, an exposition of it, with some amplification, with the aim of making clearer what he had previously stated briefly. Now all this accords with the fable of Menenius Agrippa.

“Should a dissension break out in the body, so that the feet would refuse to perform their function for the rest of the body, and the belly similarly, and the eyes, and the hands, what would be the result? Would not the result be—the destruction of the whole body?” At the same time Paul here emphasizes this one point more specifically: that each member should be content with its own place and station, and not envy the others, for he makes a comparison between the more prominent members and those with less honor.

For the eye has a more honored place in the body than the hand, and the hand than the foot. But if our hands were, from a feeling of envy, to refuse to perform their function, would nature endure this? Would the hand be listened to, when wishing to be separated from the body?

To be not of the body, means here: to have no communication with the other members, but to live for itself, and to seek only its own advantage. “Would it then,” says Paul, “be allowable for the hand to refuse to perform its function for the other members, because it envies the eyes?” These things are said about the natural body, but they must be applied to the members of the Church, lest ambition or misdirected emulation and envy cause bad feelings among us, leading one who occupies an inferior station to resent offering his services to those above him.