What role does religion play throughout the novel? What effect does it have on the lives and feelings of the characters?

To be honest, religion plays a fairly minor role in terms of affecting characters throughout the story. Very little narrative time is spent on church topics, attending worship, explaining differences between religions, or depicting specific bible references. That isn't to say that religion doesn't have an impact on the narrative plot. Holling Hoodhood is part of a Presbyterian family; however, everybody else in his school is either Catholic or Jewish. On Wednesday afternoons, the Catholic students go to Catechism and the Jewish students go to their religious studies course. This leaves Holling at school alone. The school's solution is to put him in Mrs. Baker's classroom. She is essentially a babysitter, and she and Holling both don't like the arrangement. She makes him do boring manual labor tasks like clean erasers. Eventually, Mrs. Baker begins teaching Holling Shakespeare during the Wednesday afternoons, and the relationship grows into a very deep and powerful relationship. Religion mainly served as a way to get Holling and Mrs. Baker in a classroom together in order to propel the character development forward.