On this text, those who find fault with the flesh, and contend it was no part of God's creation, attack us. What are we to say then? Just what we did before, when discusssing the Law: that as there he makes sin answerable for everything so here also. For he does not say, that the flesh works it, but just the contrary, “it is not I that do it, but sin that dwells in me.” But if he does say that “there dwells no good thing in it,” still this is no charge against the flesh. For the fact that “no good thing dwells in it,” does not show that it is evil itself. Now we admit, that the flesh is not so great as the soul, and is inferior to it, yet not contrary, or opposed to it, or evil; but that it is beneath the soul, as a harp beneath a harper, and as a ship under the pilot. And these are not contrary to those who guide and use them, but go with them entirely, yet are not of the same honor with the artist. As then a person who says, that the art resides not in the harp or the ship, but in the pilot or harper, is not finding fault with the instruments, but pointing out the great difference between them and the artist; so Paul in saying, that “in my flesh dwells no good thing,” is not finding fault with the body, but pointing out the soul's superiority. For this it is that has the whole duty or pilotage put into its hands, and that of playing. And this Paul here points out, giving the governing power to the soul, and after dividing man into these two things, the soul and the body, he says, that the flesh has less of reason, and is destitute of discretion, and ranks among things to be led, not among things that lead. But the soul has more wisdom, and can see what is to be done and what not, yet is not equal to pulling in the horse as it wishes. And this would be a charge not against the flesh only, but against the soul also, which knows indeed what it ought to do, but still does not carry out in practice what seems best to it. “For to will,” he says, “is present with me; but how to perform that which is good, I find not.” Here again in the words, “I find not,” he does not speak of any ignorance or perplexity, but a kind of thwarting and crafty assault made by sin, which he therefore points more clearly out in the next words.
<!--<span class="stiki"></span>-->Ver. 19, 20. “For the good that I would I do not: but the evil which I would not that I do. Now if I do that I would not, it is no more I that do it but sin that dwells in me.”
Do you see, how he acquits the essence of the soul, as well as the essence of the flesh, from accusation, and removes it entirely to sinful actions? For if the soul wills not the evil, it is cleared: and if he does not work it himself, the body too is set free, and the whole may be charged upon the evil moral choice. Now the essence of the soul and body and of that choice are not the same, for the two first are God's works, and the other is a motion from ourselves towards whatever we please to direct it. For willing is indeed natural (ἕ μφυτον), and is from God: but willing on this wise is our own, and from our own mind.
Ver. 21. “I find then a law, that when I would do good, evil is present with me.”
What he says is not very clear. What then is it that is said? I praise the law, he says, in my conscience, and I find it pleads on my side so far as I am desirous of doing what is right, and that it invigorates this wish. For as I feel a pleasure in it, so does it yield praise to my decision. Do you see how he shows, that the knowledge of what is good and what is not such is an original and fundamental part of our nature, and that the Law of Moses praises it, and gets praise from it? For above he did not say so much as I get taught by the Law, but “I consent to the Law;” nor further on that I get instructed by it, but “I delight in” it. Now what is “I delight?” It is, I agree with it as right, as it does with me when wishing to do what is good. And so the willing what is good and the not willing what is evil was made a fundamental part of us from the first. But the Law, when it came, was made at once a stronger accuser in what was bad, and a greater praiser in what was good. Do you observe that in every place he bears witness to its having a kind of intensitiveness and additional advantage, yet nothing further? For though it praises and I delight in it, and wish what is good the “evil is” still “present with me,” and the agency of it has not been abolished. And thus the Law, with a man who determines upon doing anything good, only acts so far as auxiliary to him, as that it has the same wish as himself. Then since he had stated it indistinctly, as he goes on he gives a yet more distinct interpretation, by showing how the evil is present, how too the Law is a law to such a person only who has a mind to do what is good.
Ver. 22. “For I delight,” he says, “in the law of God after the inward man.”
He means, for I knew even before this what was good, but when I find it set down in writing, I praise it.
Ver. 23. “But I see another law warring against the law of my mind.”
Source: Homilies on Romans (New Advent)