In terms of “explaining retinues that are formed by principal nature” (Ming Li-hsing Chüan-shu), what Chih-i attempts to convey is that every being possesses the Buddha-nature. The relationship is thus formed by this inherent nature for attaining Buddhahood. Chih-i argues that the fundamental principle of the Buddha-nature that is equally possessed by sentient beings and the Buddha is evidenced in the Buddha’s statement in the Lotus Sūtra, emphasizing that all living beings are his children. Therefore, retinues that are formed by principal nature indicate children and father relationship between sentient beings and the Buddha. (Vol. 2, Page 290-291)