St. Augustine on Becoming Holy Among Wicked Pastors

The necessity of saintly priests:

The defects of the sheep are widespread. There are very few healthy and sound sheep, few that are solidly sustained by the food of truth, and few that enjoy the good pasture God gives them. But the wicked shepherds do not spare such sheep. [...] [The wicked] kill the sheep. "How do they kill them?" you ask. By their wicked lives and by giving bad example. [...]

Even the strong sheep, if he turns his eyes from the Lord's laws and looks at the man set over him, notices when his shepherd is living wickedly and begins to say in his heart: "If my pastor lives like that, why should I not live like him?" The wicked shepherd kills the strong sheep. [...]

Let such a shepherd not deceive himself because the sheep is not dead, for though it still lives, he is a murderer--just as when the lustful man looks on a woman with desire, even though she is chaste, he has committed adultery. [...] He has not entered her bedroom, yet he has ravished her within the bedroom of his heart.

Source: St. Augustine, Sermo 46, 9: CCL 41, 535-536; Liturgy of the Hours, vol. 4, 271-272.