Orthodoxus. Then, if parts of a thing are not destructive of one another, and these are found to be so, they will not be parts of the same thing. But if they are not parts of the same thing, they will not be parts of one and the same matter. And, indeed, they will not be matter either, because nothing that exists is destructive of itself. And this being the case with the contraries, it is shown that they are not matter. This is enough on the subject of matter.
Now we must come to the examination of evils, and must necessarily inquire into the evils among men. As to these, are they forms of the principle of evil, or parts of it? If forms, evil will not have a separate existence distinct from them, because the species are to be sought for in the forms, and underlie them. But if this is the case, evil has an origin. For its forms are shown to have an origin— such as murder, and adultery, and the like. But if you will have them to be parts of some principle of evil, and they have an origin, it also must have an origin. For those things whose parts have an origin, are of necessity originated likewise. For the whole consists of parts. And the whole will not exist if the parts do not, though there may be some parts, even if the whole be not there.
Now there is nothing existing of which one part is originated, and another part not. But if I were even to grant this, then there was a time when evil was not complete, namely, before matter was wrought by God. And it attains completeness when man is produced by God; for man is the maker of the parts of evil. And from this it follows that the cause of evil being complete, is God the Creator, which it is impious to say. But if you say that evil is neither of the things supposed, but is the doing of something evil, you declare that it has an origin. For the doing of a thing makes the beginning of its existence. And besides this, you have nothing further to pronounce evil. For what other action have you to point out as such, except what happens among men? Now, it has been already shown that he who acts is not evil according to his being, but in accordance with his evil doing.
Because there is nothing evil by nature, but it is by use that evil things become such. So I say, says he, that man was made with a free-will, not as if there were already evil in existence, which he had the power of choosing if he wished, but on account of his capacity of obeying or disobeying God.
For this was the meaning of the gift of Free Will. And man after his creation receives a commandment from God; and from this at once rises evil, for he does not obey the divine command; and this alone is evil, namely, disobedience, which had a beginning.
For man received power, and enslaved himself, not because he was overpowered by the irresistible tendencies of his nature, nor because the capacity with which he was gifted deprived him of what was better for him; for it was for the sake of this that I say he was endowed with it (but he received the power above mentioned), in order that he may obtain an addition to what he already possesses, which accrues to him from the Superior Being in consequence of his obedience, and is demanded as a debt from his Maker. For I say that man was made not for destruction, but for better things. For if he were made as any of the elements, or those things which render a similar service to God, he would cease to receive a reward befitting deliberate choice, and would be like an instrument of the maker; and it would be unreasonable for him to suffer blame for his wrong-doings, for the real author of them is the one by whom he is used. But man did not understand better things, since he did not know the author (of his existence), but only the object for which he was made. I say therefore that God, purposing thus to honour man, and to grant him an understanding of better things, has given him the power of being able to do what he wishes, and commends the employment of his power for better things; not that He deprives him again of free-will, but wishes to deprives him again of free-will, but wishes to point out the better way. For the power is present with him, and he receives the commandment; but God exhorts him to turn his power of choice to better things. For as a father exhorts his son, who has power to learn his lessons, to give more attention to them inasmuch as, while he points out this as the better course, he does not deprive his son of the power which he possessed, even if he be not inclined to learn willingly; so I do not think that God, while He urges on man to obey His commands, deprives him of the power of purposing and withholding obedience. For He points out the cause of His giving this advice, in that He does not deprive him of the power. But He gives commands, in order that man may be able to enjoy better things. For this is the consequence of obeying the commands of God. So that He does not give commands in order to take away the power which He has given, but in order that a better gift may be bestowed, as to one worthy of attaining greater things, in return for his having rendered obedience to God, while he had power to withhold it. I say that man was made with free-will, not as if there were already existing same evil, which he had the power of choosing if he wished,... but that the power of obeying and disobeying God is the only cause.
For this was the object to be obtained by free-will. And man after his creation receives a commandment from God, and from this at once rises evil; for he does not obey the divine command, and this alone is evil, namely, disobedience, which had a beginning. For no one has it in his power to say that it is without an origin, when its author had an origin. But you will be sure to ask whence arose this disobedience. It is clearly recorded in Holy Scripture, by which I am enabled to say that man was not made by God in this condition, but that he has come to it by some teaching. For man did not receive such a nature as this. For if it were the case that his nature was such, this would not have come upon him by teaching. Now one says in Holy Writ, that “man has learned (evil).” I say, then, that disobedience to God is taught. For this alone is evil which is produced in opposition to the purpose of God, for man would not learn evil by itself. He, then, who teaches evil is the Serpent.
For my part, I said that the beginning of evil was envy, and that it arose from man's being distinguished by God with higher honour. Now evil is disobedience to the commandment of God.
Source: Concerning Free Will (New Advent)