First, the easy part: the title of the book, Go Down, Moses, comes from the title of the last story, "Go Down, Moses." And the title of that story comes from an old African-American spiritual of the same name. African American slaves had always seen the story of the Israelites' enslavement in Egypt as a parallel to their own enslavement, and the story of the Exodus from Egypt expressed their own hope of freedom. "Way down in Egypt land" in the song was a fitting metaphor for the South. So the title's fitting for a book about the generations that moved from slavery to freedom.
We see the close identification of African Americans with the story of the Israelite slaves in Molly Beauchamp's lament for her grandson Samuel, whom she cries was "sold to Pharaoh" by Roth Edmonds, when he threw Samuel off the plantation and into the hands of a racist society. This story obviously was hugely meaningful for her.
Samuel Beauchamp was executed about 75 years after slavery was abolished in the United States by constitutional amendment. And Molly was born a free woman. We think what Faulkner is telling us is that long, long after slavery was abolished as an institution, there were still a lot of ways that people could feel enslaved. We talk more about that in our "Themes" section.
And who would Moses be in this telling? That's something to think about.