Quotes from Akira Sadakata

A buddha's mission is to rescue living beings trapped in the worlds of transmigration. A buddha appears in the world as a result of his aspiration toward enlightenment in former existences and his accumulation of various kinds of practice in a single world system (or, some say, in a trichiliocosm, described in chapter 4). ??kyamuni, th Buddha who appeared in India, was one such buddha.