History of the Peloponnesian War
Thucydides
Thucydides. The history of the Peloponnesian War, Volume 1-2. Dale, Henry, translator. London: Heinemann and Henry G. Bohn, 1851-1852.
For our strength against the enemy lies in this. So then we must not hurt ourselves, by being strict judges of the offenders, but rather see how, by punishing them moderately, we may be able in future to avail ourselves of the cities with unimpaired mean the score of money; and we must resolve to derive our protection not from severity of laws, but from attention to deeds. The very contrary of which we do at present;
and we have subdued any power that was [once] free, and, when harshly governed, naturally revolted for its independence, we fancy that we are bound to avenge ourselves with severity.
But in dealing wit freemen, we must not punish them rigorously when revolt, but watch them rigorously before they revolt and prevent their even coming to the thought of it; and when we have mastery of them, we should attach the guilt to as few as possible.
"Now consider what an error you would commit in this also, if persuaded by Cleon.
For at present the commons in all the states are well disposed towards you, and either do not revolt with the aristocratical party, or if compelled to do so, are straightway hostile to those who made them; and you have the mass of the city opposed to you on your side, when you proceed to war.