Letters from the Franco-German yearbooks (it's in my copy, _Karl Marx early writings_, edited by Quintin Hoare and Introduced by Lucio Colletti, 1975 pbk, p 209) Letter to Arnold Ruge:
The reform of consciousness consists entirely in making the world aware of its own consciousness, in arousing it from its dream of itself, in explaining its own actions to it. Like Feuerbach's critique of religion, our whole aim can only be to translate religion and political problems into their self-conscious human form.
Our programme must be: the reform of consciousness not through dogmas but by analysing mystical consciousness obscure to itself, whether i appear in religious or political form. It will become plain that the world has long since dreamed of something of which it needs only to become conscious for it to possess it in reality. It will then become plain that our task is not to draw a sharp mental line between past and future, but to complete the thought of the past. lastly, it will become plain that mankind will not begin any new work, but will consciously bring about the completion of its old world
We are therefore in a position to sum up the credo of our journal in a single word: the self-clarification (critical philosophy) of the struggles and wishes of the age. This is a task for the world and for us. It can succeed only as the product of united efforts. What is need above all is a confession, and nothing more than that. To obtain forgiveness for its sins mankind needs only to declare them for what they are.