John Calvin on 1 Corinthians 12:19

19. If all were one member He means, that God has not acted at random, or without good reason, in assigning different gifts to the members of the body; but because it was necessary that it should be so, for the preservation of the body; for if this symmetry were taken away, there would be utter confusion and derangement. Hence we ought to submit ourselves the more carefully to the providence of God, which has so suitably arranged everything for our common advantage. One member is taken here to mean a mass, that is all of one shape, and not distinguished by any variety; for if God were to fashion our body into a mass of this kind, it would be a useless heap. “Un amas de chair inutile;” — “A heap of useless flesh.”