"That the bourgeoisie hate us so passionately is one of the most striking proofs that we are showing the people the right ways and means of overthrowing the rule of the bourgeoisie."

"Our Party's mistake is obvious. The fighting party of the advanced class need not fear mistakes. What it should fear is persistence in a mistake, refusal to admit and correct a mistake out of a false sense of shame."

"We must withdraw from Zimmerwald immediately."

"The bitterest enemies of socialism sometimes do it a service by the excessive zeal of their “exposures”. They bear down on the very things that deserve sympathy and emulation. They open the people’s eyes to the infamy of the bourgeoisie by the very nature of their attacks."