It is from Lenin's article "On the Significance of Militant Materialism."

"We must understand that without a solid philosophical basis no natural sciences, no materialism are able to struggle successfully against the pressure of bourgeois ideas and the reestablishment of the bourgeois world conception. To be up to this struggle, and to carry it successfully to the end, the natural scientist must be a contemporary materialist, a conscious follower of the materialism represented by Marx i.e., he must be a dialectical materialist. To attain this aim, the contributors to the periodical Under the Banner of Marxism must organise a systematic study of Hegel's dialectics from the materialistic point of view, i.e., the dialectics applied in a practical manner by Marx in his Capital and in his historical and political works"......

"Resting on the manner in which Marx applied the materialistically interpreted dialectic of Hegel, we can and must elaborate this dialectic from all sides, publish in the periodical excerpts from Hegel's chief works, interpret them materialistically, commenting them by samples of the application of dialectics in Marx's works, and also by samples of dialectics in the economic and political field, such as are very plentifully provided by recent history, especially, by the present imperialist war and evolution. In my opinion, the group of editors and contributors of the periodical Under the Banner of Marxism must be a kind of 'society of materialistic friends of Hegelian dialectic'. Contemporary students of natural science will find (provided they will know how to look for it, and if we learn to help them) in the materialistically interpreted dialectic of Hegel a series of answers to the philosophical questions raised by the revolution with regard to natural science, questions which lead astray into reaction the intellectual admirers of the bourgeois fashion".

 

Lenin, Article "On the Significance of Militant Materialism", Lenin Collected Works (Vol. XXVII).