I say the same of humility and of all the virtues; the wiles of the devil are terrible, he will run a thousand times round hell if by so doing he can make us believe that we have a single virtue which we have not. And he is right, for such ideas are very harmful, and such imaginary virtues, when they come from this source, are never unaccompanied by vainglory; just as those which God gives are free both from this and from pride.
Interior Castle (ed. 1961)