Plutarch De Vitioso Pudore 16

[16] For it is not because of blunders in metre in lyric songs, as Plato observes, that cities and friends are set at variance to their utter ruin and destruction, but because of their blunders with regard to law and justice. Yet there are a sort of men that can be very curious and critical in their verses and letters and lyric measures, and yet would persuade others to neglect that justice and honesty which all men ought to observe in offices, in passing judgments, and in all actions. But these men are to be dealt with after the following manner. An orator perhaps presses you to show him favor in a cause to be heard before you, or a demagogue importunes you when you are a senator: tell him you are ready to please him, on condition that he make a solecism in the beginning of his oration, or be guilty of some barbarous expression in his narration. These terms, for shame, he will not accept; for some we see so superstitiously accurate as not to allow of two vowels meeting one another. Again, you are moved by a person of quality to something of ill reputation: bid him come over the market-place at full noon dancing, or making buffoon-like grimaces; if he refuse, question him once more, whether he think it a more heinous offence to make a solecism or a grimace, than to break a law or to perjure one’s self, or to show more favor to a rascal than to an honest man. Nicostratus the Argive, when Archidamus promised him a vast sum of money and his choice of the Spartan ladies in marriage, if he would deliver up the town Cromnum into his hands, returned him this answer: He could no longer believe him descended from Hercules, he said, because Hercules traversed the world to destroy wicked men, but Archidamus made it his business to debauch those that were good. In like manner, if one that stands upon his quality or reputation presses us to do any thing dishonorable, we must tell him freely, he acts not as becomes a person of his character in the world.