The devil would be nothing, if only human beings were more careful and cautious. For when did he ever have sufficient strength to prevail over the human being except by craftiness, or by lying, by treachery, by fraud, by deception, by malice, by employing the vices, and by sins in full frenzy? He always examines human wills, and without question flees from good wills, but complies with bad wills, in order to be the servant of wickedness, the procurer of sins, and the very parasite of the vices.
Sermon 105, section 3.
