Opium of the people - Wikipedia

https://en.wikipedia.org/wiki/Opium_of_the_people
Opium of the people - Wikipedia

---

Marx believed that religion had certain practical functions in society that were similar to the function of opium in a sick or injured person: it reduced people's immediate suffering and provided them with pleasant illusions which gave them the strength to carry on. Marx also saw religion as harmful, as it prevents people from seeing the class structure and oppression around them, thus religion can prevent the necessary revolution.