[I]t is preached in the Lotus Sūtra, fascicle 5, chapter 14 on the “Peaceful Practices”: “Various gods always protect the practicer for the sake of the dharma day and night.” This means that the great King of the Brahma Heaven, Indra, the sun and moon, the Four Heavenly Kings and others will never fail to protect those who say “Namu Myōhō Renge Kyō.”
Kangyō Hachiman-shō, Remonstration with Bodhisattva Hachiman