Thucydides, History of the Peloponnesian War
Benjamin Jowett, Ed.

62. 'Such is the great advantage which we obtain by sound policy as against the Athenians. [2] And¹ why, if peace is acknowledged by all to be the greatest of blessings, should we not make peace among ourselves? Whatever good or evil is the portion of any of us, is not peace more likely than war to preserve the one and to alleviate the other? And has not peace honours and glories of her own unattended by the dangers of war? (But it is unnecessary to dilate on the blessings of peace any more than on the miseries of war.) Consider what I am saying, and instead of despising my words, may every man seek his own safety in them! [3] And should there be some one here present who was hoping to gain a permanent advantage either by right or by force, let him not take his disappointment to heart. For he knows that many a man before now who has sought a righteous revenge, far from obtaining it, has not even escaped himself; and many an one who in the consciousness of power has grasped at what was another's, has ended by losing what was his own. [4] The revenge of a wrong is not always successful merely because it is just; nor is strength most assured of victory when it is most full of hope. The inscrutable future is the controller of events, and, being the most treacherous of all things, is also the most beneficent; for when there is mutual fear, men think twice before they make aggressions upon one another.