The Buddha attained Buddhahood by understanding this Lotus Sūtra. If He does not preach the sūtra for other people, He will commit the mistake of destroying the seed of Buddhahood. Therefore, Śākyamuni Buddha appeared in this world to expound the Lotus Sūtra. Then the King of Devils in the Sixth Heaven, who is said to be the manifestation of fundamental ignorance, entered the bodies of all sentient beings, made them bear a grudge against the Buddha, and tried to interfere with His attempt.
King Virūḍhaka murdered 500 members of the Śākya Clan; Aṅgulimāla chased after the Buddha; Devadatta injured the Buddha with a huge rock; and Chinchāmānavika strapped a bowl to her belly and spread a rumor that the Buddha made her pregnant. After a Brahman king decreed that anyone who let the Buddha enter the walled city would be fined 500 taels, the people in the city erected barriers of thorny roses on streets, threw feces into wells, blocked the gates with spikes, and poisoned food. These were all caused by the King of Devils who hated the Buddha. The murder of Nun Utpalavarṇā, who was a disciple of the Buddha, the killing of Maudgalyāyana by non-Buddhists with bamboo sticks and burying the murdered body of Kālodāyin in horse dung were also caused by hatred of the Buddha on the part of the King of Devils.
Śākyamuni Buddha, however, was able to escape all kinds of persecutions and began preaching the Lotus Sūtra on a mountain called Mt. Sacred Eagle northeast of Rājagṛha in Central India. The Buddha was then 72 years old and it was the forty-second year since He began expounding the Dharma. After preaching the sūtra for eight years He passed away at the age of 80 at midnight on the 15th day of the second month by the Hiraṇyavati River at Kuśinagara in East India. Nevertheless, as He made it clear that His enlightenment was preached in the Lotus Sūtra, the words of the Lotus Sūtra are thus the very spirit of the Buddha. As each word of the sūtra represents the Buddha’s spirit, Śākyamuni Buddha will protect those who practice this sūtra as if they were His own eyes. He will accompany and protect them as a shadow follows the body. Why shouldn’t their prayers be answered?
Kitō Shō, Treatise on Prayers, Writings of Nichiren Shōnin, Faith and Practice, Volume 4, Page 60-61