The Lotus Sūtra in the 13th chapter on the “Encouragement for Upholding This Sūtra” states, “Evil monks of the defiled world who do not know that the Buddha used expedient and provisional teachings will slander and scowl at practicers of the Lotus Sūtra. We will often be chased out of monasteries.”
It is also preached in the Nirvana Sūtra, “After My extinction, there will be hundreds, thousands, and many more besides, who do not believe in the Great Nirvana Sūtra and slander it. (…) The three kinds of Buddhists practicing the teachings for śrāvaka, pratyekabuddha, and bodhisattvas will likewise hate this supreme Great Nirvana Sūtra.”
Monk Valued Opinion fell into the three evil realms (hell, realm of hungry spirits, and that of beasts and birds) because of his sin of slandering Bodhisattva Happy Root; and Thinking-of-Buddha and others suffered in the Hell of Incessant Suffering because of their sin of beating Never-Despising Bodhisattva. They all erred from not being able to distinguish between the Mahāyāna and Hinayāna and provisional and true teachings in Buddhism. As even the ignorant know that the ten evil acts and the five rebellious sins are grave crimes, they will hardly cause national destruction or the ruin of Buddhism. Consequently, it is stated in the Sūtra of the Benevolent King, “Unable to distinguish right from wrong, the king will put his faith in their (evil priests’) teachings.” It is also stated in the Nirvana Sūtra, “Those who commit the four major sins (killing, stealing, adultery and lying) and the five rebellious sins, with full knowledge of the seriousness of the sins they commit, have no abhorrence and repentance of their sins from the beginning, and no intention of confessing them.”
These scriptural passages show that slanderers of the True Dharma, themselves as well as those who believe in them, do not know the meaning of slandering, so they commit this grave sin, destroying the country and ruining Buddhism.
Sainan Taiji-shō, Treatise on the Elimination of Calamities, Writings of Nichiren Shōnin, Doctrine 1, Pages 94-95