The understanding of pathos, logos and ethos is crucial to formulating a significant and arguable thesis, which should capture the essence of your perspective on a text. The argument itself will require much more than a sentence or two, but the thesis, or the statement of the central argument, is an important tool in presenting a persuasive case. It should relay to your reader the specific point around which the rest of the argument revolves and why that point is so important.
You are encouraged to compose, early in your writing process, a working thesis. At this point, the thesis is not yet set in stone, but it will help guide your research and your logic as you formulate your case. Once you have analyzed the text, read the research on your topic, and determined your perspective and purpose, you will need to revise and refine your thesis to ensure that it sets up and controls your argument with real impact.