From the Pastoral Rule, Book I, Chapter 9:
But for the most part those who covet pastoral authority mentally propose to themselves some good works besides, and, though desiring it with a motive of pride, still muse how they will effect great things: and so it comes to pass that the motive suppressed in the depths of the heart is one thing, another what the surface of thought presents to the muser's mind. For the mind itself lies to itself about itself, and feigns with respect to good work to love what it does not love, and with respect to the world's glory not to love what it does love. Eager for domination, it becomes timid with regard to it while in pursuit, audacious after attainment. For, while advancing towards it, it is in trepidation lest it should not attain it; but all at once, on having attained, thinks what it has attained to be its just due. And, when it has once begun to enjoy the office of its acquired dominion in a worldly way, it willingly forgets what it has cogitated in a religious way. Hence it is necessary that, when such cogitation is extended beyond wont, the mind's eye should be recalled to works already accomplished, and that every one should consider what he has done as a subordinate; and so may he at once discover whether as a prelate he will be able to do the good things he has proposed to do. For one can by no means learn humility in a high place who has not ceased to be proud while occupying a low one: one knows not how to fly from praise when it abounds, who has learned to pant for it when it was wanting: one can by no means overcome avarice, when advanced to the sustentation of many, whom his own means could not suffice for himself alone.