“Often attributed to Lenin or Stalin, less often to Marx. According to the book, "They Never Said It", p. 64, the phrase derives from a rumour that Lenin said this to one of his close associates, Grigori Zinoviev, not long after a meeting of the Politburo in the early 1920s, but there is no evidence that he ever did. Experts on the Soviet Union reject the rope quote as spurious.”

Source: Wikiquote