[I]t is stated in the first “Introductory” chapter of the Lotus Sūtra that when the Buddha showed a potent omen of emitting a ray of light from the white curls between His eyebrows, Bodhisattva Maitreya saw Buddhas of the numerous worlds in the universe expound major sūtras in five periods He then asked Bodhisattva Mañjuśrī what this all meant: “The Buddhas, Saintly Masters, the Lion-like Ones, expounded the most wonderful sūtra. I also saw them teaching many billions of bodhisattvas with pure and gentle voices.” This indicates that the first preaching of the Buddha was the Flower Garland Sūtra for bodhisattvas. Also, in the “Expedients” chapter of the Lotus Sūtra the Buddha refers to His experience upon attaining enlightenment stating, “Sitting under a bodhi tree for the first time, I meditated on the tree, strolled about … then various heavenly beings such as the King of the Brahma Heaven, Indra, the Four Heavenly Kings who protect the world, and Great Freedom God and billions of their retainers respectfully held their hands in gasshō, bowed and requested Me to preach.” This passage from the Lotus Sūtra indicates when the Flower Garland Sūtra was preached. Hence the first fascicle of the Flower Garland Sūtra includes such names as moon god, sun god, Indra, King of the Brahma Heaven, and Great Freedom God, all of whom attended the assembly of the Flower Garland Sūtra.

Shugo Kokka-ron, Treatise on Protecting the Nation, Writings of Nichiren Shōnin, Doctrine 1, Page 6