For the theft which reached men then, had some advantage; not that he who perpetrated the theft had utility in his eye, but Providence directed the issue of the audacious deed to utility. I know that many are perpetually assailing us with the allegation, that not to prevent a thing happening, is to be the cause of it happening. For they say, that the man who does not take precaution against a theft, or does not prevent it, is the cause of it: as he is the cause of the conflagration who has not quenched it at the beginning; and the master of the vessel who does not reef the sail, is the cause of the shipwreck. Certainly those who are the causes of such events are punished by the law. For to him who had power to prevent, attaches the blame of what happens. We say to them, that causation is seen in doing, working, acting; but the not preventing is in this respect inoperative. Further, causation attaches to activity; as in the case of the shipbuilder in relation to the origin of the vessel, and the builder in relation to the construction of the house. But that which does not prevent is separated from what takes place. Wherefore the effect will be accomplished; because that which could have prevented neither acts nor prevents. For what activity does that which prevents not exert? Now their assertion is reduced to absurdity, if they shall say that the cause of the wound is not the dart, but the shield, which did not prevent the dart from passing through; and if they blame not the thief, but the man who did not prevent the theft. Let them then say, that it was not Hector that burned the ships of the Greeks, but Achilles; because, having the power to prevent Hector, he did not prevent him; but out of anger (and it depended on himself to be angry or not) did not keep back the fire, and was a concurring cause. Now the devil, being possessed of free-will, was able both to repent and to steal; and it was he who was the author of the theft, not the Lord, who did not prevent him. But neither was the gift hurtful, so as to require that prevention should intervene.