Karl Marx's statement that religion is the "opium of the people" is an oft-repeated maxim of those who take organised religion to be a means of social control of large populations by comparatively small elites. Presumably the picture is something like the deviant cabal of priest-kings using the carrot of heaven and the stick of hell to keep the men docile, the women breeding, and the children unquestioning. In the modern world, this translates to the propagation of propaganda by churches, mosques, temples and synagogues, by politicians who espouse religious values, and by a media that is complicit in the dispersal of moralistic and manipulative worldviews.
The response to this, or so some anti-religious figures would have us believe, should be to cast off religion altogether - to expose it for the charade of control and pacification that it really is. Overthrow the vicars! Banish the immams! Exile the rabbis! Imprison the gothis! Once this is done, every man woman and child will be free to critically appraise the world as it is. Now that they are no longer being kept in check by the far-reaching influence of the pan-global religious puppet-masters, they will rise up in order to secure the humanity that is rightly theirs!
A problem with this line of argument, whatever reality it may actually pertain to, is that it is based on a complete misunderstanding of what Marx meant when he said what he said. The full quote is as follows:
The foundation of irreligious criticism is: Man makes religion, religion does not make man. Religion is, indeed, the self-consciousness and self-esteem of man who has either not yet won through to himself, or has already lost himself again. But man is no abstract being squatting outside the world. Man is the world of man – state, society. This state and this society produce religion, which is an inverted consciousness of the world, because they are an inverted world. Religion is the general theory of this world, its encyclopaedic compendium, its logic in popular form, its spiritual point d’honneur, its enthusiasm, its moral sanction, its solemn complement, and its universal basis of consolation and justification. It is the fantastic realization of the human essence since the human essence has not acquired any true reality. The struggle against religion is, therefore, indirectly the struggle against that world whose spiritual aroma is religion.
Religious suffering is, at one and the same time, the expression of real suffering and a protest against real suffering. Religion is the sigh of the oppressed creature, the heart of a heartless world, and the soul of soulless conditions. It is the opium of the people.
(Karl Marx, Introduction to A Contribution to the Critique of Hegel's Philosophy of Right, 1844, emphasis added)
As with all philosophy, this is open to wide interpretation. One thing is clear, however. What Marx is saying is not that religion is something imposed on the people in order to make them passive in the face of suffering; rather, religion is something made by the people themselves in order that they might better cope with the suffering they face in the world in which they find themselves.
Of course, Marx very much felt that religion was a barrier between people and their own humanity. He saw its inevitable rejection as one of the most important steps on the path to communism. Indeed, the very paragraphs after the above quote talk of "plucking the flowers from the chains"; once the religious decoration people have hung around their lives is gone, the reality of their situation is more easily apparent. Once people can see the chains of modern life for what they are, they will finally be able to cast them off. None of this changes the fact, however, that Marx took religion to be symptomatic of suffering, rather than a cause of it.
Marx was responsible for some of the most profound and imporant political and philosophical writings of the modern age. That he is misquoted and misinterpreted more often than not is one of the great tragedies of philosophical exegesis. Perhaps if the real meaning of his writings on religion had been somewhat better known, those great Soviet leaders would not have been so quick to march religious dissidents to the gulags, and ultimately, to their deaths. Then again...
Marx was nothing if not immensely sympathetic to the plight of all modern peoples. Perhaps those who are so quick to criticise the religious for being too far distanced from reality should consider that, for some people, that very distance might be the difference between a life worth living, and one that seems altogether without hope.