45 “Let him that stands take heed lest he fall.” He who stands does not give way to detraction, for it is the tales of those at ease in which detraction is spread abroad, and malignity betrayed. So that the prophet says: “I have hated the congregation of the malignant, and will not sit with the ungodly.” And in the thirty-sixth Psalm, which he has filled with moral precepts, he has put at the very beginning: “Be not malignant among the malignant, neither be envious of those who do iniquity.” Malignancy is more harmful than malice, because malignancy has neither pure simplicity nor open malice, but a hidden ill-will. And it is more difficult to guard against what is hidden than against what is known. For which reason too our Saviour warns us to beware of malignant spirits, because they would catch us by the appearance of sweet pleasures and a show of other things, when they hold forth honour to entice us to ambition, riches to avarice, power to pride.
Source: Letters (New Advent)