All Buddhas appear in the world for one great purpose. Though distinctions are made as to the three vehicles, ultimately [they all] rely on the One Vehicle. Therefore Sakyamuni descended to this world to be born in the royal palace, left home, and attained the Path according to his capability. He preached many different sermons; some were at first direct and later gradual, some were at first gradual and later direct, but all were taught as inducements to the Lotus Sutra.
Gishin, The Collected Teachings of the Tendai Lotus School, p. 49