In 1938, Hitler speaks to Hermann Rauschning:
It is not Germany that will turn Bolshevist, but Bolshevism that will become a sort of National Socialism. Besides, there is more that binds us to Bolshevism than separates us from it. There is, above all, genuine revolutionary feeling, which is alive everywhere in Russia except where there are Jewish Marxists. I have always made allowance for this circumstance, and given orders that some Communists are to be admitted to the party at once. The petit bourgeois Social Democrat and the trade-union boss will never make a National Socialist, but the Communist always will.
Hermann Rauschning, Hitler Speaks: A Series of Political Conversations with Adolf Hitler on His Real Aims (London: Thornton Butterworth, 1939), p. 134, quoted in François Furet, The Passing of an Illusion: The Idea of Communism in the Twentieth Century (U. of Chicago Press, 1999), pp. 191-192.