It is not inner peace that Kant holds out to man, not otherworldly serenity or
ethereal tranquillity, but war, a bloody, unremitting war against passionate,
indomitable temptation. It is the lot of the moral man to struggle against
undutiful feelings inherent in his nature, and the more intensely he feels and
the more desperately he struggles, the greater his claim to virtue. It is the
lot of the moral man to burn with desire and then, on principle—the principle
of duty—to thwart it. The hallmark of the moral man is to suffer.