The Symposium (Banquet of the Ten Virgins)

And so those men, having been thus rejected from the divine care, and the human race having again given themselves up to error, again God sent forth, by Moses, a law to rule them and recall them to righteousness. But these, thinking fit to bid a long farewell to this law, turned to idolatry. Hence God gave them up to mutual slaughters, to exiles, and captivities, the law itself confessing, as it were, that it could not save them. Therefore, worn out with ills and afflicted, they again promised that they would obey the commandments; until God, pitying man the fourth time, sent chastity to rule over them, which Scripture consequently called the bramble. And she consuming pleasures threatens besides, that unless all undoubtingly obey her, and truly come to her, she will destroy all with fire, since there will be hereafter no other law or doctrine but judgment and fire. For this reason, man henceforth began to do righteousness, and firmly to believe in God, and to separate himself from the devil. Thus chastity was sent down, as being most useful and helpful to men. For of her alone was the devil unable to forge an imitation to lead men astray, as is the case with the other precepts.