Generally, when you use the ideas of another person you can either provide a direct quote or paraphrase those ideas in your own words. Either way, you still need to cite them.
However, in literary studies the exact language used by the author - especially for complex critical or theoretical ideas is often key to getting the idea across. In these cases, when you paraphrase, you are often watering down or loosing the essence of what the writer is saying.
So for this class, your professor would like you to :
Always quote the first time you are referring to a passage in a text or another critics ideas
Then as you go on to discuss those ideas, you can paraphrase or refer back to the quote - but always have a quote that your reader can use to know exactly what you are referring to before you use or analyze that idea or passage.
You still don't want your paper to be a patchwork of unliked or badly linked quotations! So, your quotations should still be carefully worked into the text of your argument.
Also, always remember that this assignment is not meant to just be a regurgitation of other critics ideas.
You need to use your sources as you make your own argument or analysis.
