The Apostle Paul
Romans 8:10BSB·traditional attribution

But if Christ is in you, your body is dead because of sin, yet your spirit is alive because of righteousness.

John Calvin Reformed @genevareformer

10. But if Christ be in us, etc. What he had before said of the Spirit he says now of Christ, in order that the mode of Christ’s dwelling in us might be intimated; for as by the Spirit he consecrates us as temples to himself, so by the same he dwells in us.

Matthew Henry Presbyterian @wholebiblehenry

In these verses the apostle represents two more excellent benefits, which belong to true believers. I. Life. The happiness is not barely a negative happiness, not to be condemned; but it is positive, it is an advancement to a life that will be the unspeakable happiness of the man (Rom 8:10, Rom 8:11): If Christ be in you. Observe, If the Spirit be in us, Christ is in us.

Commenting on Romans 8:10-16

John Gill Reformed Baptist @doctorgill

And if Christ be in you,.... Not as he is in the whole world, and in all his creatures, or circumscriptively, and to the exclusion of himself elsewhere; for his person is above in heaven, his blood is within the vail, his righteousness is upon his people, and his Spirit and grace are in them; and so he comes to be in them, he is...