History of the Peloponnesian War
Thucydides
Thucydides, Vol. 1-4. Smith, Charles Foster, translator. London and Cambridge, MA: Heinemann and Harvard University Press, 1919-1923.
for one who has been needlessly injured is more dangerous if he escape than an avowed enemy who expects to give and take. “Do not, then, be traitors to your own cause, but recalling as nearly as possible how you felt when they made you suffer and how you would then have given anything to crush them, now pay them back. Do not become tender-hearted at the sight of their present distress, nor unmindful of the danger that so lately hung over you, but chastise them as they deserve, and give to your other allies plain warning that whoever revolts shall be punished with death. For if they realise this, the less will you have to neglect your enemies and fight against your own allies.”
Such was Cleon's speech. After him Diodotus son of Eucrates, who in the earlier meeting had been the principal speaker against putting the Mytilenaeans to death, came forward now also and stroke as follows:
"I have no fault to find with those who have proposed a reconsideration of the question of the Mytilenaeans, nor do I commend those who object to repeated deliberation on matters of the greatest moment; on the contrary, I believe the two things most opposed to good counsel are haste and passion, of which the one is wont to keep company with folly, the other with an undisciplined and shallow mind.
As for words, whoever contends[*](Directed at Cleon's remarks, 3.38.4 ff.) that they are not to be guides of our actions is either dull of wit or has some private interest at stake—dull, if he thinks it possible by any other means to throw light on that which still belongs to the dim and distant future; self-interested, if, wishing to put through a discreditable measure, he realizes that while he cannot speak well in a bad cause, he can at least slander well and thus intimidate both his opponents and his hearers. Most dangerous of all, however, are precisely those who[*](Like Cleon, 3.38.2; 3.40.1, 3.) charge a speaker beforehand with being bribed to make a display of rhetoric.
For if they merely imputed ignorance, the speaker who failed to carry his audience might go his way with the repute of being dull but not dishonest; when, however, the charge is dishonesty, the speaker who succeeds becomes an object of suspicion, whereas if he fails he is regarded as not only dull but dishonest as well.
And all this is a detriment to the state, which is thus robbed of its counsellors through fear. Indeed it would prosper most if its citizens of this stamp had no eloquence at all, for then the people would be least likely to blunder through their influence.