First, I say that nothing is evil by its very nature, but that something is called evil by the manner of its use. For the word 'adultery' signifies the union of a man and a woman; yet if a man unites with a woman for the sake of begetting children and the continuance of the race, the union becomes a good thing. But if someone, abandoning the lawful union, outrages the marriages of others, he does a very evil deed.
The union itself is the same, but the manner of its use is not alike. The same argument applies also to fornication. The union, then, when examined apart from the manner of its use, is not evil; it becomes so only when the manner is made plain. — But murder too, I say, stands in the same way.
It becomes evil only when the manner is made plain. But murder too, I say, stands in the same way. For if someone wishes to put to death a man caught in adultery, demanding the penalty for what he dared to do, he works no evil. But if someone destroys a man who has done none of the forbidden things, for no other reason or pretext, but for the sake of stripping him of his possessions—that is, of his money or property—he does an evil deed. The deed is the same in both cases, but the manner of the deed produces the difference.
Besides these, taking another's money becomes evil by the manner of the taking. For if someone gives, sharing out of what he has, the one who receives does nothing base; but if again he takes it from an unwilling owner, or secretly, he does a wicked deed. To take what belongs to another is present in both cases, but the manner of the taking makes it be called evil—or good.
Likewise the worship of God too becomes good or evil by its manner. For if someone reveres the true God, he does a good deed; but if, forsaking Him, he reveres that which is not God, and is willing to attach the honour due to the Greater One to wood or stones, he does evil. The name of piety is the same, but the manner of its use changes what is done.