Dialectical materialism is not of course an eternal and immutable philosophy. To think otherwise is to contradict the spirit of the dialectic. Further development of scientific thought will undoubtedly create a more profound doctrine into which dialectical materialism will enter merely as structural material.

[Letter to his wife, Natalia Sedova]

In addition to the happiness of being a fighter for the cause of socialism, fate gave me the happiness of being her husband. During the almost forty years of our life together she remained an inexhaustible source of love, magnanimity, and tenderness. She underwent great sufferings, especially in the last period of our lives. But I find some comfort in the fact that she also knew days of happiness.

For forty-three years of my conscious life I have remained a revolutionist; for forty-two of them I have fought under the banner of Marxism. If I had to begin all over again I would of course try to avoid this or that mistake, but the main course of my life would remain unchanged. I shall die a proletarian revolutionist, a Marxist, a dialectical materialist, and, consequently, an irreconcilable atheist. My faith in the communist future of mankind is not less ardent, indeed it is firmer today, than it was in the days of my youth.

Natasha has just come up to the window from the courtyard and opened it wider so that the air may enter more freely into my room. I can see the bright green strip of grass beneath the wall, and the clear blue sky above the wall, and sunlight everywhere. Life is beautiful. Let the future generations cleanse it of all evil, oppression and violence, and enjoy it to the full.

Everything is relative in this world, where change alone endures.

Revolutions are always verbose.

Fascism is nothing but capitalist reaction.

Events can neither be regarded as a series of adventures nor strung on the thread of a preconceived moral. They must obey their own laws.