The Enchiridion by St. Augustine
Chapter 13.--There Can Be No Evil Where There is No Good; And an Evil Man is an Evil Good.
Accordingly, there is nothing of what we call evil, if there be nothing good. But a good which is wholly without evil is a perfect good. A good, on the other hand, which contains evil is a faulty or imperfect good; and there can be no evil where there is no good. From all this we arrive at the curious result: that since every being, so far as it is a being, is good, when we say that a faulty being is an evil being, we just seem to say that what is good is evil, and that nothing but what is good can be evil, seeing that every being is good, and that no evil can exist except in a being. Nothing, then, can be evil except something which is good. And although this, when stated, seems to be a contradiction, yet the strictness of reasoning leaves us no escape from the conclusion. We must, however, beware of incurring the prophetic condemnation: |Woe unto them that call evil good, and good evil: that put darkness for light, and light for darkness: that put bitter for sweet, and sweet for bitter.| And yet our Lord says: |An evil man out of the evil treasure of his heart bringeth forth that which is evil.| Now, what is evil man but an evil being? for a man is a being. Now, if a man is a good thing because he is a being, what is an evil man but an evil good? Yet, when we accurately distinguish these two things, we find that it is not because he is a man that he is an evil, or because he is wicked that he is a good; but that he is a good because he is a man, and an evil because he is wicked. Whoever, then, says, |To be a man is an evil,| or, |To be wicked is a good,| falls under the prophetic denunciation: |Woe unto them that call evil good, and good evil!| For he condemns the work of God, which is the man, and praises the defect of man, which is the wickedness. Therefore every being, even if it be a defective one, in so far as it is a being is good, and in so far as it is defective is evil.