For if he manages the business upon upright principles, all those who are enemies and adversaries both to him and to the candidates do everything with a view to contention, provoking daily strife, and heaping infinite scorn upon the candidates, until they have got them struck off the list, or have introduced their own favorites. In fact it is just as if some pilot had pirates sailing with him in his ship, perpetually plotting every hour against him, and the sailors, and marines. And if he should prefer favor with such men to his own salvation, accepting unworthy candidates, he will have God for his enemy in their stead; and what could be more dreadful than that? And yet his relations with them will be more embarrassing than formerly, as they will all combine with each other, and thereby become more powerful than before. For as when fierce winds coming from opposite directions clash with one another, the ocean, hitherto calm, becomes suddenly furious and raises its crested waves, destroying those who are sailing over it, so also when the Church has admitted corrupt men, its once tranquil surface is covered with rough surf and strewn with shipwrecks.
Source: On the Priesthood (New Advent)