What finally makes Janie stand up to Jody in public? What changed?

In Chapter Seven, a customer named Steve Mixon wants some chewing tobacco. Janie tries to cut it, but makes a mistake. Joe recuts the tobacoo and then begins to insult Janie terribly. For the first time, Janie retaliates. She tells Joe that he is nothing but a big voice; she tells the people in the store that when he pulls his pants down that there is nothing there. Joe is irrecoverably crushed, his manliness stripped away.

This chapter marks a turning point in Janie's character development. She learns how to stand up to Joe and uses her voice to overpower his. There are several biblical references in the chapter which indicate the importance of religion to black culture at this time. Janie is described by Joe as "older than Methusalem." Janie's speaking out against Joe is like "the thing that Saul's daughter had done to David." The characters are not strongly religious; rather, the stories of the Christian tradition are firmly embedded in black folk culture, and their narratives are more important than a belief in them.

Rather than organized religion, it is nature that fortifies and empowers Janie. She is able to split her mind and see "the shadow of herself tending store and prostrating itself before Jody" while her true self "sits under a shady tree with the wind blowing through her hair and clothes." When she is finally able to keep part of her mind centered on nature, she becomes strong enough to stand up to Joe.