The Buddha represents the original nature and the Bodhisattvas represent form and application. This is why in the Flower Adornment Sutra, the Buddha does not comment on the teachings, for the original nature that is empty has nothing to say. But the Bodhisattvas do have something to say since they apply the principles. Not only is the original nature unexplained but also no thoughts arises from it. Practice corresponds with understanding.
Understanding is the principle and practice is the application.
Buddha Shakyamuni represents our original nature. Ananda, who is foremost in hearing, represents understanding and wisdom. Kasyapa, who is foremost in asceticism, represents practice. We may also see Buddha Shakyamuni with Manjushri Bodhisattva and Universal Worthy Bodhisattva on either side of him. Land Buddhism regards Buddha Amitabha as the original nature with Guan Yin Bodhisattva representing compassion and practice, and Great Strength Bodhisattva representing wisdom and understanding.