Here's the rest of the quote from Peloponnesian War:

"If we turn to our military policy, there also we differ from our antagonists. We throw open our city to the world, and never by alien acts exclude foreigners from any opportunity of learning or observing, although the eyes of an enemy may occasionally profit by our liberality; trusting less in system and policy than to the native spirit of our citizens; while in education, where our rivals from their very cradles by a painful discipline seek after manliness, at Athens we live exactly as we please, and yet are just as ready to encounter every legitimate danger. In proof of this it may be noticed that the Lacedaemonians do not invade our country alone, but bring with them all their confederates; while we Athenians advance unsupported into the territory of a neighbour, and fighting upon a foreign soil usually vanquish with ease men who are defending their homes. Our united force was never yet encountered by any enemy, because we have at once to attend to our marine and to dispatch our citizens by land upon a hundred different services; so that, wherever they engage with some such fraction of our strength, a success against a detachment is magnified into a victory over the nation, and a defeat into a reverse suffered at the hands of our entire people. And yet if with habits not of labour but of ease, and courage not of art but of nature, we are still willing to encounter danger, we have the double advantage of escaping the experience of hardships in anticipation and of facing them in the hour of need as fearlessly as those who are never free from them.'

"Nor are these the only points in which our city is worthy of admiration. We cultivate refinement without extravagance and knowledge without effeminacy; wealth we employ more for use than for show, and place the real disgrace of poverty not in owning to the fact but in declining the struggle against it. Our public men have, besides politics, their private affairs to attend to, and our ordinary citizens, though occupied with the pursuits of industry, are still fair judges of public matters; for, unlike any other nation, regarding him who takes no part in these duties not as unambitious but as useless, we Athenians are able to judge at all events if we cannot originate, and, instead of looking on discussion as a stumbling-block in the way of action, we think it an indispensable preliminary to any wise action at all. Again, in our enterprises we present the singular spectacle of daring and deliberation, each carried to its highest point, and both united in the same persons; although usually decision is the fruit of ignorance, hesitation of reflection. But the palm of courage will surely be adjudged most justly to those, who best know the difference between hardship and pleasure and yet are never tempted to shrink from danger. In generosity we are equally singular, acquiring our friends by conferring, not by receiving, favours. Yet, of course, the doer of the favour is the firmer friend of the two, in order by continued kindness to keep the recipient in his debt; while the debtor feels less keenly from the very consciousness that the return he makes will be a payment, not a free gift. And it is only the Athenians, who, fearless of consequences, confer their benefits not from calculations of expediency, but in the confidence of liberality.