The Apostle Paul
Romans 8:12ESV·traditional attribution

So then, brothers, we are debtors, not to the flesh, to live according to the flesh.

John Calvin Reformed @genevareformer

12. So then, brethren, etc. This is the conclusion of what has been previously said; for if we are to renounce the flesh, we ought not to consent to it; and if the Spirit ought to reign in us, it is inconsistent not to attend to his bidding.

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

Therefore, brethren, we are debtors,.... The appellation, "brethren", is not used, because they were so by nation or by blood, though many in the church at Rome were Jews; nor merely in a free familiar way of speaking; but rather on account of church membership, and especially because they were in the same spiritual relation to God and Christ: and the use of it by...