17 Be not led by the multitude of those who sin, neither let the host of those who perish tempt you to say secretly: “What? Must all be lost who live in cities? Behold, they continue to enjoy their property, they serve churches, they frequent baths, they do not disdain cosmetics, and yet they are universally well-spoken of.” To this kind of remark I have before replied and now shortly reply again that the object of this little work is not to discuss the clergy but to lay down rules for a monk.
The clergy are holy men and their lives are always worthy of praise. Rouse yourself then and so live in your monastery that you may deserve to be a clergyman, that you may preserve your youth from defilement, that you may go to Christ's altar as a virgin out of her chamber. See that you are well-reported of without and that women are familiar with your reputation but not with your appearance. When you come to mature years, if, that is, you live so long, and when you have been chosen into the ranks of the clergy either by the people of the city or by its bishop, act in a way that befits a clergyman, and choose for your models the best of your brothers. For in every rank and condition of life the bad are mingled with the good.
Source: Letters (New Advent)