A specter is haunting Europe - the specter of communism.

In the national struggles of the proletarians of the different countries, they point out and bring to the front the common interest of the entire proletariat, independently of all nationality.

In all of human history no country or no people have suffered such terrible slavery, conquest and foreign oppression and no country and no people have struggled so strenuously for their emancipation than Sicily and the Sicilians.

Parliamentary cretinism: that peculiar malady which since 1848 has raged all over the Continent, which holds those infected by it fast in an imaginary world and robs them of all sense, all memory, all understanding of the rude external world.

...the realm of freedom does not commence until the point is passed where labor under the compulsion of necessity and of external utility is required.

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)

Experience praises the most happy the one who made the most people happy.