What is contained in Lenin’s method was in the main already contained in the teachings of Marx, which, according to Marx himself, were “in essence critical and revolutionary.”(…) As a matter of fact, Lenin’s method is not only the restoration of, but also the concretisation and further development of the critical and revolutionary method of Marx, of his materialist dialectics.

Some think that Leninism is the precedence of practice over theory in the sense that its main point is the translation of the Marxist theses into deeds, their “execution”; as for theory; it is alleged that Leninism is rather unconcerned about it.

I must declare that this more than odd opinion about Lenin and Leninism is quite wrong and bears no relation whatever to the truth; that the attempt of practical workers to brush theory aside runs counter to the whole spirit of Leninism and is fraught with serious dangers to the work.

Theory is the experience of the working-class movement in all countries taken in its general aspect. Of course, theory becomes purposeless if it is not connected with revolutionary practice, just as practice gropes in the dark if its path is not illumined by revolutionary theory. But theory can become a tremendous force in the working-class movement if it is built up in indissoluble connection with revolutionary practice;

I must add to this that saying that Marx only cared about theory is such an absurd lie that only revisionists could come up with it, the man was exiled from multiple countries and persecuted until his last days because of his definitely practical participation in proletarian movements.