The Enchiridion

All things that exist, therefore, seeing that the Creator of them all is supremely good, are themselves good. But because they are not, like their Creator, supremely and unchangeably good, their good may be diminished and increased. But for good to be diminished is an evil, although, however much it may be diminished, it is necessary, if the being is to continue, that some good should remain to constitute the being. For however small or of whatever kind the being may be, the good which makes it a being cannot be destroyed without destroying the being itself.

An uncorrupted nature is justly held in esteem. But if, still further, it be incorruptible, it is undoubtedly considered of still higher value. When it is corrupted, however, its corruption is an evil, because it is deprived of some sort of good. For if it be deprived of no good, it receives no injury; but it does receive injury, therefore it is deprived of good. Therefore, so long as a being is in process of corruption, there is in it some good of which it is being deprived; and if a part of the being should remain which cannot be corrupted, this will certainly be an incorruptible being, and accordingly the process of corruption will result in the manifestation of this great good.

But if it do not cease to be corrupted, neither can it cease to possess good of which corruption may deprive it. But if it should be thoroughly and completely consumed by corruption, there will then be no good left, because there will be no being. Wherefore corruption can consume the good only by consuming the being. Every being, therefore, is a good; a great good, if it can not be corrupted; a little good, if it can: but in any case, only the foolish or ignorant will deny that it is a good. And if it be wholly consumed by corruption, then the corruption itself must cease to exist, as there is no being left in which it can dwell.