Wherefore let them not envy us, to whom God has revealed the truth: who, as we know that fortune is nothing, so also know that there is a wicked and crafty spirit who is unfriendly to the good, and the enemy of righteousness, who acts in opposition to God; the cause of whose enmity we have explained in the second book. He therefore lays plots against all; but those who are ignorant of God he hinders by error, he overwhelms with folly, he overspreads with darkness, that no one may be able to attain to the knowledge of the divine name, in which alone are contained both wisdom and everlasting life. Those, on the other hand, who know God, he assails with wiles and craft, that he may ensnare them with desire and lust, and when they are corrupted by the blandishments of sin, may impel them to death; or, if he shall have not succeeded by stratagem, he attempts to cast them down by force and violence. For on this account he was not at once thrust down by God to punishment at the original transgression, that by his malice he may exercise man to virtue: for unless this is in constant agitation, unless it is strengthened by continual harassing, it cannot be perfect, inasmuch as virtue is dauntless and unconquered patience in enduring evils. From which it comes to pass that there is no virtue if an adversary is wanting. When, therefore, they perceived the force of this perverse power opposed to virtue, and were ignorant of its name, they invented for themselves the senseless name of fortune; and how far this is removed from wisdom, Juvenal declares in these verses:—