Being human means throwing your whole life on the scales of destiny when need be, all the while rejoicing in every sunny day and every beautiful cloud.

Those who don't move don't notice their chains.

The more that social democracy develops, grows, and becomes stronger, the more the enlightened masses of workers will take their own destinies, the leadership of their movement, and the determination of its direction into their own hands.

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

What do you want with these special Jewish pains? I feel as close to the wretched victims of the rubber plantations in Putamayo and the blacks of Africa with whose bodies the Europeans play ball… I have no special corner in my heart for the ghetto: I am at home in the entire world, where there are clouds and birds and human tears.

The high stage of world-industrial development in capitalistic production finds expression in the extraordinary technical development and destructiveness of the instruments of war.

History is the only true teacher, the revolution the best school for the proletariat.