I have made a vow to study all the Buddhist sūtras completely at once just as Grand Master T’ien-t’ai had compared the superiority of all the sūtras, by relying on the scriptures of the sūtras alone as his guide.

Thus determined, I read through all the scriptures of Buddhism, finding that the Nirvana Sūtra states: “Depend on the dharma, not on people.” The dharma means all the sūtras preached by the Buddha; and people refers to all except the Buddha, that is, such bodhisattvas as Samantabhadra and Mañjuśrī as well as the various masters of the schools mentioned above. It also states: “Depend on the sūtra revealing the whole truth, not on the sūtras which do not reveal the whole truth.” The sūtras revealing the whole truth correspond to the Lotus Sūtra.

Hōon-jō, Essay on Gratitude, Writings of Nichiren Shōnin, Doctrine 3, Pages 4.