The quote's been posted, but it's really more of an observation; it's a symptom of the state of things, and should be interpreted through that lens. Think of it less as a moral evil and more as the 19th century equivalent of our bullshit Treat Discourse. People saw religion as a path to salvation from their very real, material problems, even though it's just a way of interpreting our perception of the world. It's less common today, at least in America. Now we have Elon worship and the rise and grind hustle culture bullshit, and whatever else people fixate on as they yearn to be free of the yoke of oppression in the various forms it takes.

Marx isn't anti-religion because "lol man in the sky silly". Marx is anti-religion because it is the product of an inverted world, a class society. Marx believes that, if class society is abolished, if the topsy-turvy (this is the word he uses in e.g. "On 'The Jewish Question'" or the rest of "Contribution to the Critique of Hegel's Philosophy of Law") world is turned upright, religion will wither away into nothing. Marx believes this is only possible when all the social relations that underlie society are laid bare in an understandable form (i.e. with communism), and that it will not disappear until the topsy-turvy material world disappears.

As Marx states in the former essay, Marx doesn't believe religion can be abolished by decree (and he points out that state secularism is often just reskinned Christianity). In both essays, Marx actually details how the state itself, money itself, are religions; for Marx religion is the work of human mind alienated from humans and dominating them.

In the full quote (which emizeko posted) Marx outright refers to religion as the general theory of this world (i.e. the topsy-turvy world), as an encyclopaedic compendium. Elsewhere (either in Contribution to the Critique or in On the Jewish Question) Marx refers to religion as a register of the theoretical struggles of mankind. Based on Marx's usage of various bible quotes and themes in his work (even Capital), it seems likely that he treated religion as he would e.g. liberal economists or members of parliament (i.e. with critical analysis and an eye towards useful stuff for his own critique)

Marx meant that religion provides an outlet for the material problems of the oppressed and thus runs counter to revolutionary action at its core. We know this doesn't mean religious people can't be revolutionary, but he did make a good point about it having the capacity to distract or to act as a substitute for demanding material change.

I recently heard a local Muslim religious leader give a speech about Palestine. This particular person decided to focus on "the" meaning of hijab (it of course means different things in different contexts) and to then say that as Muslims, it must be understood that this unbearable suffering in Palestine is only temporary, that it can be accepted because the afterlife will vindicate them.

On one hand, I would not criticize anyone for using religion as a way to heal from oppression. At the same time, you can see how "only the next life matters" could lead someone to place less emphasis on materially fighting against oppression and therefore do a worse job of opposing it.

We of course see this kind of thing in all religions, they provide explanations for injustice that usually place blame outside of what can be materially helped and justice that is entirely outside the scope of our lives. Many have the same basic idea that this life is temporary and doesn't matter in comparison to the infinite later (whatever that might be).

When it comes to organized religion, one can also see how it becomes merged with the ruling class, becoming an inherent component of social order and control and adapting its beliefs to what is needed by the ruling class. For example, early Christianity was pretty clear about all interest on debts counting as usury. There was no distinction in language whatsoever. But the Roman ruling class depended on debt, so the distinction was invented and suddenly there were good moneylenders and bad moneylenders and the ruling class's status quo was - you guessed it - good moneylenders!

Anyways, I'm getting off-track. Marx was talking about religion offering a false consciousness that detracts from revolutionary behavior.

I do think I should probably mention something else, though: many communist movements attempted to impose atheism and/or very strict secularism on populations that were not receptive to it and thereby shot themselves in the foot. It's good to understand Marx's point about what religion can offer and do but to not take it to a false extreme that deposing religion is the first priority. You'll end up, ironically, actually feeding organized religion that will redirect revolution away from being proletarian, as the people you should be able to recruit and radicalize will instead go to the alternatives, including religious organizations.

He's saying that religion takes the pain out of peoples lives by giving them ideas that make living less painful. Marx wants to get rid of the material conditions that cause suffering, so that people will no longer need religion.

The quote is about using materialist political movement to mitigate peoples suffering, not really about religion.

anticommunists chop it to a sentence or two. read the quote with more context:

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.

The abolition of religion as the illusory happiness of the people is the demand for their real happiness. To call on them to give up their illusions about their condition is to call on them to give up a condition that requires illusions. The criticism of religion is, therefore, in embryo, the criticism of that vale of tears of which religion is the halo.

from https://www.marxists.org/archive/marx/works/1843/critique-hpr/intro.htm

The quote means something like this: "Religion is used as a way to escape the crushing reality of the world and dull the meaninglessness of being a common person"

Imagine if you broke your leg. You'd very much welcome some opium (or painkillers in a modern setting) but we all know the solution is to go to the hospital and get it fixed. Marx is warning against mistaking the lack of pain for healing.

Religion is a way to soothe the pain of capitalism/feudalism but it would be better for that pain not to exist.

Reading the whole quote, especially that whole paragraph, it appears that Marx is saying that opium is both medicine and drug. It is both a comfort and an escape. It's a way for dealing with the suffering of reality -- without actually engaging with reality. At least that's my read.

Marxism is usually against religion, but it also isn’t utopian, it recognizes (indirectly) that it’s basically impossible to eradicate. Someone will always be suffering no matter how autonomous and luxurious and gay the communist society is. There will always be some sort of opium for the masses as a result.

I say usually because there have been self proclaimed Marxists who did great damage to the movement by being obsessed with religion like Pol Pot or random hippie terrorists who casually read Marx and think abusing their members is revolutionary

Though Marx is ultimately anti religion, there are several passages in which he laments the corruption of religion. That it’s supposed to be the worship of god, but instead it has been captured and repurposed into the worship of man and capital with a supernatural guise.

Since others have posted the full quote, I'll post Samir Amin's interpretation of it:

Nevertheless, another reading can be made of Marx. The often cited phrase--"religion is the opium of the people"--is truncated. What follows this remark lets it be understood that human beings need opium, because they are metaphysical animals who cannot avoid asking themselves questions about the meaning of life. They give what answers they can, either adopting those offered by religion or inventing new ones, or else they avoid worrying about them.

In any case, religions are part of the picture of reality and even constitute an important dimension of it. It is, therefore, important to analyze their social function, and in our modern world their articulation with what currendy constitutes modernity: capitalism, democracy, and secularism... It will be seen that the [Abrahamic] religions in question have been subject to successive interpretations, which have enabled them to survive, adapt to gigantic social transformations, and even participate in those transformations.

I should point out that Marx certainly wasn't against religion in the same way as his contemporaries like Bruno Bauer or Max Stirner. Those two in particular were edgy fedora style atheists of their time. They saw religion as simple ignorance or society wide brainwashing. They viewed religion as holding tendrils around a person's mind, and once that was broken, a person could achieve freedom. Marx saw a person's freedom as intrinsic to their material and social conditions. Religion is there as medicine to soothe suffering caused by a lack of freedom.

Socialist states have typically had to grapple not simply with religion, but religious organizations. The Orthodox church in the Soviet Union for instance was previously an aspect of the administrative state for Tsarist Russia. Those kind of organs don't simply disappear overnight, they have to be uprooted. The church acted as social infrastructure for Russian/etc peasants. The school, tax collector, bureaucracy, library, hospital. Sometimes all of that was contained within the local church. You can't have a socialist administrative state if you have a remnant of the previous society integrated within people's lives like that. A person's religion should be entirely their own choice, not something they're forced to rely upon.

Cuba as another example bans private religious schools. A democratic society wouldn't have schools that are unaccountable to the public. It's not the responsibility of religious organizations to plug in the gaps. There shouldn't be any need to resort to religion to house the homeless or feed people. China took a huge step and has its own internal branch of Catholicism so there's not a constant flow of money out of their country and into the Vatican. No socialist country has banned religion outright, because there's no need. There is however a need to clamp down on unaccountable organizations acting as reserve social services.

For modern interpretations one can read "opium" as "morphine".

Whenever you are reading any literature you have to be concious of the historical period the writer, at the time they were writing the book you're reading, lived in.

An example of this, using Stalin as an example, is looking at how different the world was in 1901 when Stalin wrote The Russian Social-Democratic Party and its Immediate Tasks and 1952 when Stalin wrote Economic Problems of Socialism in the USSR.

This means working to understand what they are saying within the historical context of when they lived and not applying your own modern perceptions onto their works - at least not initially in my opinion.

I'll add another Marx quote:

“Criticism has plucked the imaginary flowers on the chain not in order that man shall continue to bear that chain without fantasy or consolation, but so that he shall throw off the chain and pluck the living flower.”

Marx was simply saying that capitalist reality is so painful that people fall back on religion to ease the pain (hence “opium”) which is counter-productive because they need to realize that human agency is what ultimately change the course of history.

Religion is hence “dangerous” in the sense that people have surrendered their agency to a “higher power” and no longer feel they are the ones that have to do the work to change the world.

what if he had said that religion is like freakin crack