When Queen Māyā became pregnant with her child, the future Śākyamuni Buddha, the Demon King of the Sixth Heaven saw through her womb and said: “The queen is pregnant with a sharp sword called the Lotus Sūtra, which is our sworn enemy. How can we eliminate it before it is born?” Pretending to be a great doctor, the Demon entered the palace of King Śuddhodana and talked the queen into drinking poison, saying it was medicine effective for easy childbirth. At the very moment when the Buddha was born, the Demon King caused a rain of stones to fall and mixed the baby’s milk with poison. When Prince Siddhārtha left the palace to become a monk, the Demon King, this time, pretended to be a black poisonous snake blocking the prince’s way. Furthermore, the Demon King entered the bodies of Devadatta, Kokālika, King Virūḍhaka, and King Ajātaśatru, making them throw huge rocks at the Buddha to draw blood or to kill members of the Śākya people and Buddha’s disciples. These almost fatal obstacles to the Buddha were the work of the Demon King of the Sixth Heaven to stop the Buddha from preaching the Lotus Sūtra. They are what is referred to when the Lotus Sūtra, chapter 10 on “The Teacher of the Dharma,” mentions, “Many people hate it with jealousy even in My lifetime.” These were the difficulties the Buddha experienced quite early in His lifetime, and many terrible difficulties awaited Him later. Since Śāriputra, Maudgalyāyana, and the other great bodhisattvas could not believe in the Lotus Sūtra, they, in spite of living close to the Buddha, were the worst enemies in the forty or so years before the Lotus Sūtra was preached.

These things happened in the Buddha’s lifetime, and in the future, more horrible difficulties will probably occur as predicted in the chapter which says: “It will be worse after I die.” How can ordinary people bear those difficulties while even the Buddha could hardly bear them? How much more so, as the difficulties we are to face are said to be more tremendous than those that the Buddha had encountered! No difficulties seem more horrible than Devadatta’s attempted murder of the Buddha with a huge rock thirty feet long and sixteen feet wide or King Ajatasatru’s attempt to hurt the Buddha by releasing a drunken elephant. Nevertheless, according to the sūtra, we shall encounter difficulties greater than those. One who often encounters such difficulties, through no fault of his own, must be a practicer of the Lotus Sūtra after the Buddha’s death.

Hōon-jō, Essay on Gratitude, Writings of Nichiren Shōnin, Doctrine 3, Pages 8.