It is necessary to be able to withstand all this, to agree to any and every sacrifice, and even—if need be—to resort to all sorts of stratagems, manoeuvres and illegal methods, to evasion and subterfuges in order to penetrate the trade unions, to remain in them, and to carry on Communist work in them at all costs.

Reported in "'Left-Wing' Communism, An Infantile Disorder", V. I. Lenin; Selected Works (1938), vol. 10, p. 95.