Śākyamuni Buddha’s last words state that it is not non-Buddhist religions but Buddhists themselves that will destroy Buddhism, just as an insect living inside the body of a lion will eat up its flesh. In fact, some Buddhists destroy Mahāyāna teachings through Hinayana teachings while others extinguish the true Mahāyāna teachings by the provisional Mahāyāna teachings. These people, however, cannot exterminate the true Mahāyāna teaching of the Lotus Sūtra just as non-Buddhist religions cannot destroy Buddhism.

Hōmon Mōsaru-beki-yō no Koto, The Way to Refute the Evil Teaching, Writings of Nichiren Shōnin, Biography and Desciples, Volume 5, Page 150

[T]he parable of a gold stick is often used to discuss the Three Vehicles (teachings for śrāvaka, pratyekabuddha and bodhisattvas). It is said that a gold stick was snapped into three, each of which was given to those with the capacity to understand the Three Vehicles, saying that as each of the three is gold, they do not have to try to find the differences or to discuss which is better among them. This parable sounds reasonable, but in fact the logic is wrong and misunderstood by those who have learned a wrong doctrine.

To further clarify matters, there is an instance when the Buddha took out of the Lotus Sūtra a gold stick used as an expedient teaching, and swung it three times for those with the capacity to know the Three Vehicles. Those who could not recognize this as an expedient teaching believed that the stick was made of genuine gold and thought that they were following the right teachings. If the gold stick were snapped into three in reality, the parable would not make sense. Although the Buddha just swung the gold stick three times instead of snapping it, ignorant people with the capacity to know the Three Vehicles thought that He did break the stick into three. To say it repeatedly, it is a blunder and an error to hold this view.

The Buddha swung the stick three times not to show the Wonderful Dharma of the Lotus Sūtra, but to give the merits of an expedient teaching in the Lotus Sūtra to those who have the capacity to know the Three Vehicles. Therefore, the Three Vehicles, if put back into the expedient teaching of the Lotus Sūtra, are called an expedient teaching within the Lotus Sūtra; they will never become the “perfect teaching.” Remembering this, we should clearly see that there exists the expedient and the True teachings both inside and outside the Lotus Sūtra.

Shoshū Mondō-shō, Questions and Answers Regarding Other Schools, Writings of Nichiren Shōnin, Doctrine 3, Page 181-182

What we should chant all the time as the practice of the perfect teaching is “Namu Myōhō Renge Kyō,” and what we should keep in mind is the way of meditation based on the truth of “3,000 existences contained in one thought.” Only wise men practice both chanting “Namu Myōhō Renge Kyō” and meditating on the truth of “3,000 existences contained in one thought.” Lay followers of Japan today should recite only “Namu Myōhō Renge Kyō.” As the name has the virtue of reaching the body for which it stands, when one chants “Namu Myōhō Renge Kyō” one will not fail to receive all the merit of the Lotus Sūtra.

Jisshō-shō, A Treatise on the Ten Chapters of the Great Concentration and Insight, Writings of Nichiren Shōnin, Doctrine 2, Page 4

QUESTION: According to the Nirvana Sūtra, the sūtras preached before it all contain false views. What do you think of that?

ANSWER: The Buddha’s purpose of appearing in the world was to preach the Lotus Sūtra, in which He preaches in the second chapter on the “Expedients”, “My old wish has already been fulfilled; it is indeed the time now to expound the Mahāyāna teaching definitively;” and in the 16th chapter on “The Life Span of the Buddha, actually, however, Good Men, I have been the Buddha since eternal past.” Nevertheless, regarding the comparative superiority in doctrine, the Buddha Himself declares in the 10th chapter on the “Teacher of the Dharma,” that although He has expounded numerous, thousands, tens of thousands and hundred millions of sūtras, the Lotus Sūtra is superior to all the sūtras which have already been preached, are being preached, and will be preached. Then, in the 11th chapter on the “Appearance of the Stupa of Treasures,” the Buddha of Many Treasures appeared from underground testifying: “What has been said by Śākyamuni Buddha is all true,” while various Buddhas, the manifestations of Śākyamuni Buddha in the worlds all over the universe, stretched out their tongues to reach the Brahma Heaven attesting the words of Śākyamuni to be true.

Thus, the comparative superiority between the Lotus Sūtra and all other sūtras has been resolved by Śākyamuni Buddha, the Buddha of Many Treasures, and Buddhas manifested in worlds all over the universe. No further comparison between the Lotus Sūtra and sūtras preached before and after it is necessary because they are all preached by the one Śākyamuni Buddha.

Therefore, when the Nirvana Sūtra rejects sūtras preached before it, the Lotus Sūtra is not included, because the Nirvana Sūtra, too, is trying to say that the Lotus Sūtra is superior to others.

Shugo Kokka-ron, Treatise on Protecting the Nation, Writings of Nichiren Shōnin, Doctrine 1, Page 12-13

Generally speaking, all sūtras of Śākyamuni Buddha do not contain any lies because they all were preached to save all the people. When I restudy Buddhism however, it is clear that there is a difference between Great and Lesser Vehicles, expedient and true teachings, and exoteric and esoteric teachings although they are all words of Śākyamuni Buddha. This is clearly indicated in those sūtras and has been discussed by Buddhist scholars.

In essence, there are some doubts about the truth of the teachings preached by Śākyamuni Buddha during the first forty years of His fifty years of preaching. In the Muryō-gi-kyō (Sūtra of Infinite Meaning) Śākyamuni Buddha Himself declares: “I never preached the true teaching during the first forty years.” This means that all those sūtras preached before the Lotus Sūtra are expedient. He also says in the second chapter on “Expedients” in the Lotus Sūtra: “I, Śākyamuni Buddha, have simply discarded expedient teachings, and now preach only the unsurpassed way,” concluding definitely that the sūtras preached during the first forty some years are expedient.

Moreover, it is stated in the “Appearance of a Stupa of Treasure” chapter of the Lotus Sūtra that the Buddha of Many Treasures of the Treasure-Purity World appeared from underground attesting that the Lotus Sūtra preached by Śākyamuni Buddha is nothing but the truth, while various Buddhas in manifestation, gathered from all over the universe to attend the preaching of the Lotus Sūtra, sticking out their tongues to testify that not even one character of the Lotus Sūtra is a lie.

Gassui Gasho, A Letter on Menstruation, Nyonin Gosho, Letters Addressed to Female Followers, Page 28-30

There lived a man named Young Ascetic in the Himalayas, who mastered the Brahman dharma in the Himalayas, but had never learned of Buddhism. One day an evil spirit appeared and said to him, “Everything in the universe is impermanent. This is the law of birth and death.” Revealing only the first half (eight characters) of the verse, the demon left the second half unsaid. Although Young Ascetic was glad to hear the first half of the verse, he felt as though he had been given only half of a wish-fulfilling gem or a tree that flowers without bearing fruits. So, he requested the demon to reveal the remaining half of the verse. The evil spirit responded: “I have not eaten anything for several days. I am starving so my mind is too troubled to tell the rest of it to you. Give me something to eat first.”

Young Ascetic asked, “What do you eat?”

“I eat living human flesh and blood. Since I can fly freely, I flew around the world in a flash looking for food. However, there was none to be found as I cannot kill innocent people because the gods protect them,” said the evil spirit.

Young Ascetic replied, “I will offer you my body, so tell me the remainder of the verse.”

“You are clever. Is this some kind of trick you intend to deceive me with?” the evil spirit replied.

“Young Ascetic said, ‘If someone offers you to exchange your trash for gold, wouldn’t you do it? If I die in this mountain, the birds and beasts will eat me so there won’t be any merit in my body. But if I can exchange my body for your teaching, it will be like exchanging excrement for food.’

“I’m still suspicious of your intentions,” said the evil spirit.

“I will call King Mahābrahman, Indra, Sun Deity, Moon Deity and the Four Heavenly Kings,” said Young Ascetic, “to be witnesses and pledge before them as Buddhas in the past have done.”

Finally, the evil spirit agreed to teach the rest of the verse. Young Ascetic removed his deerskin clothes, laid them on the ground, kneeled down placing his palms together in gasshō, and had the evil spirit sit on the seat. The evil spirit took his place on the seat and preached: “Extinguishing the cycles of birth and death, one is at ease and full of peace.”

Upon hearing the rest of the verse, Young Ascetic wrote it down on trees and rocks, then threw himself into the mouth of the evil spirit. This Young Ascetic is the current Śākyamuni Buddha and the evil spirit is Indra today.

Nichimyō Shōnin Gosho, A Letter to Nichimyō Shōnin, Writings of Nichiren Shōnin, Followers II, Volume 7, Page 137-138