Concerning Man's Perfection in Righteousness

XII. “Again the question arises,” he says, “how it is that man is unable to be without sin,—by his will, or by nature? If by nature, it is not sin; if by his will, then will can very easily be changed by will.” We answer by reminding him how he ought to reflect on the extreme presumption of saying—not simply that it is possible (for this no doubt is undeniable, when God’s grace comes in aid), but—that it is “very easy” for will to be changed by will; whereas the apostle says, “The flesh lusteth against the spirit, and the spirit against the flesh: and these are contrary the one to the other; so that ye do not the things that ye would.” He does not say, “These are contrary the one to the other, so that ye will not do the things that ye can,” but, “so that ye do not the things that ye would.” How happens it, then, that the lust of the flesh which of course is culpable and corrupt, and is nothing else than the desire for sin, as to which the same apostle instructs us not to let it “reign in our mortal body;” by which expression he shows us plainly enough that that must have an existence in our mortal body which must not be permitted to hold a dominion in it;—how happens it, I say, that such lust of the flesh has not been changed by that will, which the apostle clearly implied the existence of in his words, “So that ye do not the things that ye would,” if so be that the will can so easily be changed by will? Not that we, indeed, by this argument throw the blame upon the nature either of the soul or of the body, which God created, and which is wholly good; but we say that it, having been corrupted by its own will, cannot be made whole without the grace of God.