In the final analysis, it does not hurt when we strike the air with a fist, but it hurts when we strike a rock. Likewise, the sin of killing an evil man is light compared to that of killing a virtuous man; or killing an unrelated person is like striking dirt with our fist but murdering our parents is like striking a rock. A dog barking at a deer will not have its skull broken, but a dog barking at a lion will have its entrails rotted. The asura demon that swallows the sun and moon has its head split into seven [pieces], and Devadatta who struck the Buddha fell into hell through a fissure in the ground. Namely, the seriousness of a sin depends on the party affected by the crime. In this sense, the Lotus Sūtra is the eyes of all the Buddhas and the true teacher of Lord Śākyamuni Buddha. Therefore, anyone who abandons even one character or one dot of the sūtra commits a sin more serious than that of murdering 1,000 or 10,000 parents. Accordingly such person will be in the Hell of Incessant Suffering for an innumerably long period of time known as 3,000 or 500 (million) dust-particle kalpa.

Kyōdai-shō, A Letter to the Ikegami Brothers, Writings of Nichiren Shōnin, Volume 6, Followers I, Page 73-74