Marxist–Leninist atheism (Russian: Марксистско-ленинский атеизм), also known as Marxist-Leninist scientific atheism, is a part of the wider Marxist–Leninist philosophy (the type of Marxist philosophy found in the Soviet Union), which was irreligious and anti-clerical,[1][2] while at the same time advocating a materialist understanding of nature.[3][4] Marxism–Leninism holds that religion is the opium of the people, in the sense of promoting passive acceptance of suffering on Earth in the hope of eternal reward. Therefore, Marxism–Leninism advocates the abolition of religion and the acceptance of atheism.[5] In addition, Marxist-Leninist scientific atheism purports to explain "the origin of religion", as well as what it teaches to be "scientific criticism of it".[3] Marxist–Leninist atheism has its roots in the philosophy of Ludwig Feuerbach, G.W.F. Hegel, Karl Marx, and Vladimir Lenin.[6]