tut tut. mustn't refer to marx's early works. nothing but a left hegelian then. so, not the "real" marx and so, not the "real" word. at any rate, here's the full quote which i think is much more illuminating:
Religious misery is in one way the expression of real misery, and in another a protest against real misery. Religion is the sigh of the afflicted creature, the soul of a heartless world, as it is also the spirit of spiritless conditions. It is the opium of the people. The abolition of religion as the illusory happiness of the world is the demand for their real happiness. The demand to abandon the illusions about their condition is the demand to give up a condition that requires illusions. Hence criticism of religion is in embryo a criticism of this vale of tears whose halo is religion.
Criticism has plucked the imaginary flowers from the chain, not for the purpose of enabling man to wear the existing chain without fantasy or consolation, but to make him cast off the chain and cull the living flower. The criticism of religion disillusions man so that he thinks, acts, and shapes his reality like a disillusioned man who has come to his senses, so that he revolves around himself and thereby around his real sun. Religion is only the illusory sun that revolves around man so long as he does not revolve around himself.
It is, therefore, the task of history, after the otherworldly truth has disappeared, to establish the truth of this world. It is the immediate task of philosophy, which stands in the service of history, to expose human self-alienation in its unholy form after it has been unmasked in its holy form. Criticism of heaven thus is transformed into criticism of earth, criticism of religion into criticism of law, and criticism of theology into criticism of politics.
The weapon of criticism, to be sure, cannot replace the criticism of weapons; material force must be overthrown by material force, but theory itself becomes a material force as soon as the masses grip it. Theory is capable of gripping the masses when it demonstrates ad hominem, and it demonstrates ad hominem when it becomes radical. To be radical is to grasp things by the root. But for man, the root is man himself. The clear proof of the radicalism of German theory, and hence of its practical energy, is that it issues from the decisive, positive suspension of religion. The criticism of religion ends with the doctrine that man is the highest being for man, hence with the categorical imperative to overthrow all conditions in which man is a degraded, enslaved, abandoned, contemptible being
"Toward the Critique of Hegel's Philosophy of Law. Introduction"