John Calvin Commentary Romans 7:18

"For I know that in me, that is, in my flesh, dwelleth no good thing: for to will is present with me, but to do that which is good [is] not." — Romans 7:18 (ASV)

For I know, etc. He says that no good by nature dwelled in him. Then in me, means the same as if he had said, “As far as I am concerned.” In the first part he indeed arraigns himself as being wholly depraved, for he confesses that no good dwelled in him; and then he adds a modification, lest he slight the grace of God which also dwelled in him, but was no part of his flesh.

And here again he confirms the fact that he did not speak of men in general, but of the faithful, who are divided into two parts—the remnants of the flesh, and grace. For why was the modification made, unless some part was exempt from depravity, and therefore not flesh?

Under the term flesh, he always includes all that human nature is, everything in man, except the sanctification of the Spirit. In the same manner, by the term spirit, which is commonly opposed to the flesh, he means that part of the soul which the Spirit of God has so re-formed and purified from corruption, that God’s image shines forth in it. Then both terms, flesh as well as spirit, belong to the soul; but the latter to that part which is renewed, and the former to that which still retains its natural character.

To will is present, etc. He does not mean that he had nothing but an ineffectual desire, but his meaning is that the work really done did not correspond to his will, for the flesh hindered him from doing perfectly what he did. So also understand what follows, The evil I desire not, that I do: for the flesh not only impedes the faithful, so that they cannot run swiftly, but it also sets before them many obstacles at which they stumble.

Hence they fail to do what they would, because they do not accomplish it with the proper alacrity. This, to will, then, which he mentions, is the readiness of faith, when the Holy Spirit so prepares the godly that they are ready and strive to render obedience to God. But as their ability is not equal to what they wish, Paul says that he did not find what he desired, even the accomplishment of the good he aimed at.