History of the Peloponnesian War

And the way whereby we, and whosoever else hath dominion hath gotten it, hath ever been the cheerful succouring of their associates that required it, whether they were Greeks or barbarians. For if we should all sit still, or stand to make choice which were fit to be assisted and which not, we should have little under our government of the estates of other men, but rather hazard our own.

For when one is grown mightier than the rest, men use not only to defend themselves against him when he shall invade, but to anticipate him, that he invade not at all. Nor is it in our power to be our own carvers how much we will have subject to us; but considering the case we are in, it is as necessary for us to seek to subdue those that are not under our dominion, as to keep so those that are; lest if others be not subject to us, we fall in danger of being subjected unto them.

Nor are we to weigh quietness in the same balance that others do, unless also the institution of this state were like unto that of other states. Let us rather make reckoning by enterprising abroad to increase our power at home, and proceed on our voyage that we may cast down the haughty conceit of the Peloponnesians and show them the contempt and slight account we make of our present ease by undertaking this our expedition into Sicily.

Whereby, either conquering those states we shall become masters of all Greece, or weaken the Syracusians, to the benefit of ourselves and our confederates. And for our security to stay, if any city shall come to our side, or to come away if otherwise, our galleys will afford it.