What are the motifs in The Golden Ass by Apuleius?

Religious Duty is a recurring idea. In Chapter 18, the story takes a wholly unexpected turn. Up to that point in the story, Lucius' adventures are humorous and it would not seem that there is any overarching moral to the story. However, when Lucius finally regains his human form through the intervention of the goddess Isis, he commits himself to an entirely new way of life. He repents his many sexual escapades and how he constantly strove to fulfill his every desire. He decides to instead devote himself to a life of chastity and, at least relative, asceticism.