History of the Peloponnesian War

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.