Nāgārjuna and Vasubandhu were great commentators who wrote one thousand commentaries. However, they commented only on provisional Mahāyāna sūtras, and even though they inwardly grasped the Lotus Sūtra, they did not outwardly speak of it. (There is an oral transmission about this). T’ien-t’ai and Dengyō spread the Lotus Sūtra but they did not reveal the Most Venerable One of the essential section, the four bodhisattvas guided by the Original True Buddha, precept dais of the essential section, and the five characters of “Namu Myōhō Renge Kyō.” Their reasons were, first of all they did not receive the teaching from the Buddha. Secondly the time was not right to spread the teaching. The time has now arrived, however, and the four bodhisattvas guided by the Original True Buddha will appear in this world to spread the True Dharma according to the sūtra. I, Nichiren, have known this for a while. During the time of Emperor Wu in Han China a blue bird flew from the West signaled the omen of Hsi-wang-mu’s coming or a magpie sang as the omen of a visiting guest. My disciples should think this through seriously. You should not abandon your faith in the Lotus Sūtra even at the risk of your life.

Hokke Gyōja Chinan-ji, Difficulty of the Practicer of the Lotus Sūtra, Writings of Nichiren Shōnin, Biography and Disciples, Volume 5, Pages 16