One major theme is the importance of family and friends. Daniel starts the novel isolated from everyone he knew, set apart from his village and without any ties to his former life. Through his deepening friendship with Joel and Thacia, Daniel discovers that his former life not only mattered, but that he possessed a deeper connection to it than he ever realized.
"You thought I had forgotten," he said. "But I remember how it used to be when Leah and I first came to live with you. Your hair was still so black, Grandmother. You worked in the ketzah field that summer. But at night you used to tell us stories."
(Speare, The Bronze Bow, Google Books)
After this scene, in which Daniel reconnects with his sister as their grandmother dies, Daniel discovers that he cannot return to his life with the bandits as he had lived it before. His heart has been reborn into caring about his family, and his friendship with Thacia has reminded him -- although he resists it -- that people are not meant to live alone. By the end of the novel, Daniel has realized that his life with his family and the villagers is more important than revenge, and that forgiveness is a more powerful tool than violence.
Love covers a multitude of sins.