Excerpt from Gregory the Great: The Book of Pastoral Rule, c. 590

The conduct of a prelate ought so far to be superior to the conduct of the people as the life of a shepherd is accustomed to exalt him above the flock. For one whose position is such that the people are called his flock ought anxiously to consider how great a necessity is laid upon him to maintain uprightness. It is necessary, then, that in thought he should be pure, in action firm; discreet in keeping silence; profitable in speech; a near neighbor to every one in sympathy; exalted above all in contemplation; a familiar friend of good livers through humility, unbending against the vices of evil-doers through zeal for righteousness; not relaxing in his care for what is inward by reason of being occupied in outward things, nor neglecting to provide for outward things in his anxiety for what is inward.

The pastor should always be pure in thought, inasmuch as no impurity ought to pollute him who has undertaken the office of wiping away the stains of pollution in the hearts of others also; for the hand that would cleanse from dirt must needs be clean, lest, being itself sordid with clinging mire, it soil all the more whatever it touches. The pastor should always be a leader in action, that by his living he may point out the way of life to those who are put under him, and that the flock, which follows the voice and manners of the shepherd, may learn how to walk rather through example than through words. For he who is required by the necessity of his position to speak the highest things is compelled by the same necessity to do the highest things. For that voice more readily penetrates the hearer's heart, which the speaker's life commends, since what he commands by speaking he helps the doing by showing.

The pastor should be discreet in keeping silence, profitable in speech; lest he either utter what ought to be suppressed or suppress what he ought to utter. For, as incautious speaking leads into error, so indiscreet silence leaves in error those who might have been instructed. The pastor ought also to understand how commonly vices pass themselves off as virtues. For often niggardliness excuses itself under the name of frugality, and on the other hand extravagance conceals itself under the name of liberality. Often inordinate carelessness is believed to be loving-kindness, and unbridled wrath is accounted the virtue of spiritual zeal. Often hasty action is taken for promptness, and tardiness for the deliberation of seriousness. Whence it is necessary for the pastor of souls to distinguish with vigilant care and vices between virtues and vices, lest stinginess get possession of his heart while he exults in seeming frugality in expenditure; or, while anything is recklessly wasted, he glory in being, as it were, compassionately liberal; or, in overlooking what he ought to have smitten, he draw on those that are under him to eternal punishment; or, in mercilessly smiting an offense, he himself offend more grievously; or, by rashly anticipating, mar what might have been done properly and gravely; or, by putting off the merit of a good action, change it to something worse.

Since, then, we have shown what manner of man the pastor ought to be, let us now set forth after what manner he should teach. For, as long before us Gregory Nazianzen, of reverend memory, has taught, one and the same exhortation does not suit all, inasmuch as all are not bound together by similarity of character. For the things that profit some often hurt others; seeing that also, for the most part, herbs which nourish some animals are fatal to others; and the gentle hissing that quiets horses incites whelps; and the medicine which abates one disease aggravates another; and the food which invigorates the life of the strong kills little children. Therefore, according to the quality of the hearers ought the discourse of teachers to be fashioned, so as to suit all and each for their several needs, and yet never deviate from the art of common edification. For what are the intent minds of hearers but, so to speak, a kind of harp, which the skillful player, in order to produce a tune possessing harmony, strikes in various ways? And for this reason the strings render back a melodious sound, because they are struck indeed with one quill, but not with one kind of stroke. Whence every teacher also, that he may edify all in the one virtue of charity, ought to touch the hearts of his hearers out of one doctrine, but not with one and the same exhortation.