John Calvin Commentary 1 Corinthians 15:37

"and that which thou sowest, thou sowest not the body that shall be, but a bare grain, it may chance of wheat, or of some other kind;" — 1 Corinthians 15:37 (ASV)

You sow not that body that will spring up. This comparison consists of two parts — first, that it is not surprising that bodies rise from decay, since the same thing happens with seed; and secondly, that it is not contrary to reason that our bodies should be restored in a different condition, since, from bare grain, God brings forth so many ears of corn, fashioned with admirable design, and filled with grains of superior quality.

However, since by speaking in this way he might seem to suggest that many bodies will therefore rise out of one, he modifies his statement in another way, by saying that God forms the body as it pleases Him, meaning that in this regard also there is a difference in quality.

He adds, to every seed its own body. By this clause he restricts what he had said concerning a different body; for he says that, while the body is different, it nevertheless retains its particular kind.