Karl Marx, in the Introduction to A Contribution to the Critique of Hegel's Philosophy of Right:
The criticism of religion ends with the teaching that man is the highest being for man - hence, with the categoric imperative to overthrow all relations in which man is a debased, enslaved, abandoned, despicable being...Enslaved by other human beings; abandoned in this world; debased by one or another belief system; despicable because of who he is and not because of what he has done.