Complex sentence: 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-and it therefore promotes the abolition of religion and the acceptance of atheism.
Split into simpler sentences: 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.