...the Communists everywhere support every revolutionary movement against the existing social and political order of things... They openly declare that their ends can be attained only by the forcible overthrow of all existing social conditions.

In every revolution there intrude, at the side of its true agents, men of a different stamp; some of them survivors of and devotees to past revolutions, without insight into the present movement, but preserving popular influence by their known honesty and courage, or by the sheer force of tradition; others mere brawlers, who, by dint of repeating year after year the same set of stereotyped declamations against the government of the day, have sneaked into the reputation of revolutionists of the first water They are an unavoidable evil: with time they are shaken off.

Religion is the balm of the people.

If emancipation of the working classes requires their fraternal conncurrence, how are they to fulfill that great mission with a foreign policy in pursuit of criminal designs, playing upon national prejudices, and squandering in piratical wars the people's blood and treasure? It was not the wisdom of the ruling classes, but the heroic resistance to their criminal folly by the working classes of England, that saved the west of Europe from plunging headlong into an infamous crusade for the propagation of slavery on the other side of the Atlantic.

When the sufferers learn to think, then the thinkers will learn to suffer.

Once the inner connection is grasped, all theoretical belief in the permanent necessity of existing conditions collapses before their collapse in practice -- Letter to Ludwig Kugelmann (July 11, 1868)

Life is not determined by consciousness, but consciousness by life.