A thesis statement is the sentence that states what you are going to prove in your essay (no matter what kind of essay you are writing). It should be found at the very end of your introductory paragraph. Your thesis statement should be proved in your body paragraphs using examples from your primary source as well as quotations from your primary source.
When speaking about the form of any essay, we begin with the introduction. You can begin the introduction in any way you would like: with a general statement about your subject, a quotation, maybe a story, etc. After that, you filter your introduction down to its last sentence. As has already been indicated, your last sentence of the introduction should be your thesis.
The next part of any essay will be the body paragraphs. Each body paragraph should begin with a topic sentence that relates directly back to your thesis. The rest of the body paragraph should be used to prove that topic sentence. You should use direct examples from the literary work as well as quotations. Don't forget to EXPLAIN them as a part of your body paragraph!
The final part of your essay will be your conclusion which, of course, begins with a reworded thesis statement. This simply means that you take your original thesis statement and use different words to say the same thing. Then introduce your reader to a new idea, sum up your essay, and end with a neat clincher (something that the reader can remember).
A thesis statement is one to two sentences that is the main idea(s) of your your essay.
A thesis statement is your way of telling the reader what is going to happen in your essay. It's to show what focus you are taking in your interpretation of the topic you are looking at. For example, if you are doing an essay on Shakespeare's treatment of female characters, your normal introduction will state that you will look at characters a, b and c from certain texts. Your thesis statement in this case would propose how you are going to look at these characters and the general sense of what you will say. It would say perhaps that you are going to argue that Shakespeare creates passive female characters with no voice. A thesis statement, therefore, is much more focused than a general introduction.