Depends. You can spend the conclusion synthesizing the information you have presented in your essay, concluding with a reiteration of what you have proved (your thesis statement), or you can restate your thesis at the beginning and then move on to talk about the larger significance of your point.
Oh, I recently had the insight that:
1.) The thesis is the core of the essay, a single sentence at the end of para #1
2.) The whole essay is that same idea in several paragraphs, and
3.) the conclusion paragraph is that same idea restated in one paragraph.
So #1 is the central message as a sentence, #2 is the central message as a whole essay, and #3 is the central message as a paragraph.
You can be a little free in the conclusion paragraph. Restate the thesis at the start and then give the reader more reasons to care. capture the important points you made throughout the essay, ut capture the in 1 or 2 sentences. Conclude with a call to action, perhaps.