History of the Peloponnesian War

Men of Boeotia, it ought never to have so much as entered into the thought of any of us the commanders that, because we find not the Athenians now in Boeotia, it should therefore be unfit to give them battle. For they out of a bordering country have entered Boeotia and fortified in it with intent to waste it, and are indeed enemies in whatsoever ground we find them, or whencesoever they come doing the acts of hostility.

But now if any man think it also unsafe, let him henceforth be of another opinion. For providence, in them that are invaded, endureth not such deliberation concerning their own as may be used by them who, retaining their own, out of desire to enlarge, voluntarily invade the estate of another.