Romans VIII. 12, 13
Therefore, brethren, we are debtors, not to the flesh, to live after the flesh. For if you live after the flesh, you shall die; but if you through the Spirit do mortify the deeds of the body, you shall live.
After showing how great the reward of a spiritual life is, and that it makes Christ to dwell in us, and that it quickens our mortal bodies, and wings them to heaven, and renders the way of virtue easier, he next fitly introduces an exhortation to this purpose. Therefore we ought not to live after the flesh. But this is not what he says, for he words it in a much more striking and powerful way, thus, we are debtors to the Spirit. For saying, we are debtors not to the flesh, indicates this. And this is a point he is everywhere giving proof of, that what God has done for us is not matter of debt, but of mere grace. But after this, what we do is no longer matter of free-will offering, but of debt. For when he says, You are bought with a price, be not ye the servants of men; and when he writes, You are not your own; and again in another passage he calls these selfsame things to their mind, in these words, If (most manuscripts om. if) One died for all, then all died that they should not henceforth live unto themselves. And it is to establish this that he says here also, We are debtors; then since he said we are not debtors to the flesh, lest you should again take him to be speaking against the nature of the flesh, he does not leave speaking, but proceeds, to live after the flesh. For there are many things which we do owe it, as giving it food, warmth, and rest, medicine when out of health, clothing, and a thousand other attentions. To prevent your supposing then that it is this ministration he is for abrogating when he says, We are not debtors to the flesh, he explains it by saying, to live after the flesh. For the care that I am for abrogating is, he means, that which leads to sin, as I should be for its having what is healing to it. And this he shows further on. For when he says, Make not provision for the flesh, he does not pause at this, but adds, to fulfil the lusts thereof. And this instruction he gives us here also, meaning, Let it have attention shown it indeed, for we do owe it this, yet let us not live according to the flesh, that is, let us not make it the mistress of our life. For it must be the follower, not the leader, and it is not it that must regulate our life, but the laws of the Spirit must it receive. Having then defined this point, and having proved that we are debtors to the Spirit, to show next for what benefits it is that we are debtors, he does not speak of those past (a thing which serves as a most striking proof of his judgment), but those which were to come; although even the former were enough for the purpose. Yet still he does not set them down in the present case, or mention even those unspeakable blessings, but the things to come. For a benefit once for all conferred does not, for the most part, draw men on so much as one which is expected, and is to come. After adding this then, he first uses the pains and ills that come of living after the flesh, to put them in fear, in the following words; For if you live after the flesh you shall die, so intimating to us that deathless death, punishment, and vengeance in hell. Or rather if one were to look accurately into this, such an one is, even in this present life, dead. And this we have made clear to you in the last discourse. But if you through the Spirit, do mortify the deeds of the body, you shall live. You see that it is not the essence of the body whereof we are discoursing, but the deeds of the flesh. For he does not say, if you through the Spirit do mortify the essence of the body, but the deeds of it, and these not all deeds, but such as are evil. And this is plain in what follows: for if you do this, you shall live, he says. And how is it in the nature of things for this to be, if it was all deeds that his language applied to? For seeing and hearing and speaking and walking are deeds of the body; and if we mortify these, we shall be so far from living, that we shall have to suffer the punishment of a manslayer. What sort of deeds then does he mean us to mortify? Those which tend toward wickedness, those which go after vice, which there is no other way of mortifying save through the Spirit. For by killing yourself you may put an end to the others. And this you have no right to do. But to these (you can put an end) by the Spirit only. For if This be present, all the billows are laid low, and the passions cower under It, and nothing can exalt itself against us. So you see how it is on things to come, as I said before, that he grounds his exhortations to us, and shows that we are debtors not owing to what has been already done only. For the advantage of the Spirit is not this only, that He has set us free from our former sins, but that He renders us impregnable against future ones, and counts us worthy of the immortal life. Then, to state another reward also, he proceeds: