Those lines begin a poem called "The Second Coming" by the Irish poet William Butler Yeats. Chinua Achebe took his title from those lines. BUt I cite them because they offer a hint into Richard Wright's Native Son as well. In fact, these lines might be a good way to open your essay.
Analyze the conflict of both works. The conflict is derived from plot. What is happening to the protagonists, the main characters. Conflict comes in several forms, usually rendered as "man v. man," "man v. nature," "man v. society," or "man v. himself." I would suggest that both Wright and Achebe write books that are more complex than to find only one conflict, but you might be better off for the purpose of your paper to center in on only one conflict, a major one. Something common to both books is the conflict of man against society. And even though there are other conflicts in the novels, I suggest that man v. society is the big one -- most overt, most important, most readily seen.
When you trace moral and ethical implications, you want to examine things like guilt effects on both the individuals of the novel, the reader, and the society of the novel and the society in which the reader lives. Sometimes these are the same, sometimes they are not. RIchard Wright, for instance, points out the absurdity of life for an African-American in Chicago in the early 1930's; but the lifestyle and problems of Bigger Thomas are emblematic of the society in general. Bigger would not have gotten into his situation had he not been black. (Since you invoked my name in your post I take it you've already read my commentaries on Native Son here at SparkNotes. If not, you can run a search.)
Chapter two of Achebe's novel is a good place to start in your comparison. The night setting of that chapter is closely aligned to the setting of Wright's book, especially in the crucial scene where Bigger kills Mary. The contrast of black and white (snow, the white blur) in Wright is emblematic...