It is also said in the Nirvana Sūtra that we should rely only upon sūtras that completely reveal the truth, not upon sūtras that do not completely reveal the truth. This means that we must distinguish the true sūtra from provisional ones before relying upon it. In the Commentary on the Ten Stages by Bodhisattva Nāgārjuna, it is also said that we should rely upon the just commentaries on sūtras and not upon evil ones. Grand Master T’ien-t’ai says, “Adopt whatever agrees with the sūtra, and do not believe in that which is not found in the sūtra in word or in meaning;” while Grand Master Dengyō states, “Rely upon the words of the Buddha in sūtras; do not believe in what has been transmitted orally.” Enchin, the Grand Master Chishō, states that we should transmit the Buddha’s teaching only from sūtras.

Kaimoku-shō, Open Your Eyes to the Lotus Teaching, Writings of Nichiren Shōnin, Doctrine 2, Page 84-85