Social democracy.. is only the advance guard of the proletariat, a small piece of the total working masses; blood from their blood, and flesh from their flesh.

Self-criticism, cruel, unsparing criticism that goes to the very root of the evil, is life and breath for the proletarian movement.

The most revolutionary act is a clear view of the world as it really is.

Social democracy.. is only the advance guard of the proletariat, a small piece of the total working masses; blood from their blood, and flesh from their flesh.

The working classes in every country only learn to fight in the course of their struggles.

Only through the conscious action of the working masses in city and country can it be brought to life, only through the people's highest intellectual maturity and inexhaustible idealism can it be brought safely through all storms and find its way to port.

Only to the rude ear of one who is quite indifferent does the song of a bird seem always the same.