The Lotus Sūtra does not expound anything extraordinary. The sūtra preaches that Śākyamuni Buddha had attained Buddhahood already 500 (million) dust particle kalpa in the past and that even the Two Vehicles such as Śāriputra, who are considered incapable of becoming Buddhas, will inevitably attain Buddhahood in the future. Therefore, those who do not believe in these two doctrines will fall into the Hell of Incessant Suffering. It is not I alone who say this. The Buddha of Many Treasures and numerous Buddhas in manifestation from all over the universe verified this. Numerous bodhisattvas emerged from the earth, direct disciples of the Original and True Buddha, as well as Mañjuśrī, Avalokiteśvara, King of the Brahma Heaven, Indra, the sun and moon, the Four Heavenly Kings, ten female rākṣasa demons, and others promised to protect the Lotus Sūtra. As such there is no other way leading to Buddhahood. It is the Lotus Sūtra that explains the past and future with precision and upholding this sūtra is the way to attain Buddhahood.

Seichōji Daishū-chū, A Letter to the People of the Seichōji Temple, Writings of Nichiren Shōnin, Volume 5, Page 177