John Calvin Commentary Romans 8:10

"And if Christ is in you, the body is dead because of sin; but the spirit is life because of righteousness." — Romans 8:10 (ASV)

But if Christ be in us, etc. What he had previously said of the Spirit he now says of Christ, so that the manner of Christ’s dwelling in us might be indicated; for as by the Spirit he consecrates us as temples to himself, so by the same he dwells in us. But what we have previously referred to, he now explains more fully — that the children of God are counted spiritual, not on the basis of a full and complete perfection, but only on account of the newness of life that has begun in them. And he anticipates here a cause for doubt, which might have otherwise disturbed us; for though the Spirit possesses a part of us, we still see another part yet under the power of death. He then gives this answer — that the power of quickening is in the Spirit of Christ, which will be effective in swallowing up our mortality. Therefore, he concludes that we must patiently wait until the remnants of sin are entirely abolished.

Readers have already been reminded that by the word Spirit they should not understand the soul, but the Spirit of regeneration. Paul calls the Spirit life, not only because he lives and reigns in us, but also because he quickens us by his power, until finally, having destroyed the mortal flesh, he perfectly renews us.

So, on the other hand, the word body signifies that unrefined mass which is not yet purified by the Spirit of God from earthly impurities, which delights in nothing but what is unrefined. For it would be otherwise absurd to ascribe to the body the fault of sin. Besides, the soul is so far from being life that it does not live by itself. The meaning of Paul then is — that although sin condemns us to death insofar as the corruption of our first nature remains in us, yet the Spirit of God is its conqueror. Nor is it any hindrance that we are only favored with the first-fruits, for even one spark of the Spirit is the seed of life.