6 You see, my excellent friend, that the man who is powerful in preaching has peculiar need of greater study than others; and besides study, of forbearance also greater than what is needed by all those whom I have already mentioned. For thus are many constantly springing up against him, in a vain and senseless spirit, and having no fault to find with him, but that he is generally approved of, hate him; and he must bear their bitter malice nobly, for as they are not able to hide this cursed hatred, which they so unreasonably entertain, they both revile, and censure, and slander in private, and defame in public, and the mind which has begun to be pained and exasperated, on every one of these occasions, will not escape being corrupted by grief.
For they will not only revenge themselves upon him by their own acts, but will try to do so by means of others, and often having chosen some one of those who are unable to speak a word, will extol him with their praises and admire him beyond his worth. Some do this through ignorance alone, some through ignorance and envy, in order that they may ruin the reputation of the other, not that they may prove the man to be wonderful who is not so, and the noble-minded man has not only to struggle against these, but often against the ignorance of the whole multitude; for since it is not possible that all those who come together should consist of learned men, but the chances are that the larger part of the congregation is composed of unlearned people, and that even the rest, who are clearer headed than they, fall as far short of being able to criticize sermons as the remainder again fall short of them; so that only one or two are seated there who possess this power; it follows, of necessity, that he who preaches better than others carries away less applause, and possibly goes home without being praised at all, and he must be prepared to meet such anomalies nobly, and to pardon those who commit them in ignorance, and to weep for those who acquiesce in them on account of envy as wretched and pitiable creatures, and not to consider that his powers have become less on either of these accounts. For if a man, being a pre-eminently good painter, and superior to all in his art, sees the portrait which he has drawn with great accuracy held up to ridicule, he ought not to be dejected, and to consider the picture poor, because of the judgment of the ignorant; as he would not consider the drawing that is really poor to be something wonderful and lovely, because of the astonishment of the inartistic.
Source: On the Priesthood (New Advent)