It is preached in the Lotus Sūtra, fascicle 7 (“Medicine King Bodhisattva” chapter), “This sūtra is a good medicine for the diseases of the people of the Jambudvīpa.” Bear in mind that this scriptural statement is preached in the Lotus Sūtra. Although the holy teachings of the Buddha preached during His lifetime are all the words of the Buddha, which from the eternal past have never been in error, this Lotus Sūtra especially is the most truthful of all the true teachings as Śākyamuni Buddha Himself states, “Having abandoned the expedients, I preach this sūtra honestly.” This is why the Buddha of Many Treasures bore witness to the truth of the Lotus Sūtra and various Buddhas gathered from all the worlds throughout the universe stretched their tongues ̄to touch the Brahma Heaven. How then can the Lotus Sūtra be false?

Kaen Jōgō Gosho, Writing About Lengthening the Life Span, Writings of Nichiren Shōnin, Volume 7, Followers II, Pages 112-113