“With the unleashing of a mighty clash of peoples, the bourgeoisie is playing its last card and calls forth on the world scene that which Karl Marx called the sixth great power: the socialist revolution.”

Source: Les Misérables

"In the Storm" in Le Socialiste http://www.marxists.org/archive/luxemburg/1904/05/01.htm as translated by Mitch Abidor (1 - 8 May 1904)
Context: The Russo-Japanese War now gives to all an awareness that even war and peace in Europe – its destiny – isn’t decided between the four walls of the European concert, but outside it, in the gigantic maelstrom of world and colonial politics.
And its in this that the real meaning of the current war resides for social-democracy, even if we set aside its immediate effect: the collapse of Russian absolutism. This war brings the gaze of the international proletariat back to the great political and economic connectedness of the world, and violently dissipates in our ranks the particularism, the pettiness of ideas that form in any period of political calm.
The war completely rends all the veils which the bourgeois world – this world of economic, political and social fetishism – constantly wraps us in.
The war destroys the appearance which leads us to believe in peaceful social evolution; in the omnipotence and the untouchability of bourgeois legality; in national exclusivism; in the stability of political conditions; in the conscious direction of politics by these “statesmen” or parties; in the significance capable of shaking up the world of the squabbles in bourgeois parliaments; in parliamentarism as the so-called center of social existence.
War unleashes – at the same time as the reactionary forces of the capitalist world – the generating forces of social revolution which ferment in its depths.

This seems to first appear in Why Leaders Can't Lead : The Unconscious Conspiracy Continues (1989) by Warren G. Bennis, p. 159, where it is cited as being from a letter to Thomas Jefferson, but it might be a misquote of "Great necessities call out great virtues" stated in a letter to her son John Quincy Adams (19 January 1780)
Disputed

As quoted in The Myth of the Nation and the Vision of Revolution: The Origins of Ideological Polarization in the 20th Century, Jacob Talmon, University of California Press (1981) p. 487
Undated

April 18, 1934. Attributed by Winston Churchill in Vol. 1 of The Second World War. (1948)
Disputed

Napoleon the Little (1852), Book V, V
Napoleon the Little (1852)

"A Plan for Spam" http://www.paulgraham.com/spam.html, August 2002

In jail, Cross-Country Kline to Dove Linkhorn.
Source: A Walk on the Wild Side (1956)
Context: But blow wise to this, buddy, blow wise to this: Never play cards with a man called Doc. Never eat at a place called Mom's. Never sleep with a woman whose troubles are worse than your own. Never let nobody talk you into shaking another man's jolt. And never you cop another man's plea. I've tried 'em all and I know. They don't work. / Life is hard by the yard, son. But you don't have to do it by the yard. By the inch it's a cinch. And money can't buy everything. For example: poverty.