It is stated in the Lotus Sūtra, fascicle 2, chapter 3 on “A Parable,” “If a person does not believe in but slanders this sutra, he will immediately destroy all the seeds for attaining Buddhahood in this world.” It is because one aspect of having no faith in this sūtra causes others to abandon the Lotus Sūtra. Interpreting this, Bodhisattva Vasubandhu, therefore, states in the first fascicle of his Treatise on the Buddha-nature, “He who hates and contradicts Mahāyāna becomes an icchantika (one who has no goodness in his nature and therefore, no possibility of attaining Buddhahood) because such a person causes people to abandon this dharma.”

Shugo Kokka-ron, Treatise on Protecting the Nation, Writings of Nichiren Shōnin, Doctrine 1, Page 30-31