When a good monk sees someone trying to destroy the teachings

"Answer: Your lack of understanding is great indeed! I am reminded of the words of clear warning that the Scholar Manoratha gave to his disciple, Bodhisattva Vasubandhu, as is written [in The Record of the Western Regions]. “Manoratha said, ‘Do not attempt to argue over important principles with the supporters of the various cliques; do not try to define what is doctrinally correct when dealing with bands of deluded persons!’ After he had delivered these words, he died.”

Your lack of understanding is like that of the groups he mentions. But as it happens, the Buddha, the World-Honored One, when he was preaching the Lotus Sutra, in the course of that one sutra twice gave instructions regarding its transmission.

Moreover, when preaching another sutra, the Nirvana Sutra, he indicated how the Lotus Sutra was to be transmitted. Thus in the Nirvana Sutra he stated: “If even a good monk sees someone destroying the teaching and disregards him, failing to reproach him, to oust him, or to punish him for his offense, then you should realize that that monk is betraying the Buddha’s teaching.” The two Tripitaka masters, Shan-wu-wei and Chin-kang-chih, and the two great teachers, Jikaku and Chishō, were doing just that, using the Mahāvairochana Sutra, which is one of the sutras embodying the provisional teachings, to destroy the Lotus Sutra, a sutra of the true teaching.

Therefore if I, Nichiren, fearful of the world, should fail to speak out, I would be the enemy of the Buddha. Hence the Great Teacher Chang-an has delivered his warning to students of the latter age, saying: “One who destroys or brings confusion to the Buddha’s teachings is betraying them. If one befriends another person but lacks the mercy to correct him, one is in fact his enemy. But one who reprimands and corrects an offender . . . is acting as his parent.”

I have taken these words of Chang-an’s commentary thoroughly to heart, and therefore I risk my life to speak out in reprimand. I remember that Āryadeva, the fourteenth successor to Shakyamuni’s teachings, was murdered, and Āryasimha, the twenty-fifth successor, had his head cut off."