It is stated in the Collection Concerning the Immediate Attainment of Buddhahood by Grand Master Jikaku:

“The Buddha’s wish to teach and save the people is fulfilled in the Lotus Sūtra. Thus, the Buddha emerges in this world and expounds the Lotus Sūtra. While practicing the bodhisattva way before attaining Buddhahood, various Buddhas take four great vows to save the people by causing them to eliminate delusions, master the teaching of the Buddha, and attain Buddhahood. If they complete the practice and are endowed with its resulting merits, they can fulfill the last three vows of the Four Great Vows. However, it is difficult for them to accomplish the first vow to lead the people and enable them to eliminate delusions. Not even the Flower Garland Sūtra can enable the people in the Ten Realms (from the realm of Buddhas to hell) to attain Buddhahood. The same is true with the Āgama sūtras, the Hōdō (various Mahāyāna) sūtras, and the Wisdom Sūtra. Though expounding all the teachings again after the Lotus Sūtra, the Nirvana Sūtra cannot accomplish the Buddha’s will to enable all the people to attain Buddhahood. Now it becomes clear that all living beings of the Ten Realms can attain Buddhahood by the teaching of the Lotus Sūtra. Devadatta who had once fallen into the Hell of Incessant Suffering was assured in the Lotus Sūtra to become Heavenly King Buddha; the daughter of a dragon king and the ten female rākṣasa demons attained Buddhahood; an asura demon was assured of future Buddhahood, and bodhisattvas in the realm of men, heavenly beings and the Two Vehicles and all bodhisattvas who mastered the teachings other than the Lotus Sūtra are all able to enter the perfect realm of the Buddha. It is preached in the “Expedient” chapter of the Lotus Sūtra that the Buddha has accomplished His Vow to lead all the people to the way of the Buddha. Since the realm of men is limitless, there still are people who have not entered the way of the Buddha. However, all the people of the Ten Realms will surely attain Buddhahood solely by the strength of the Lotus Sūtra. The Lotus Sūtra fulfills the will of the Buddha to save all the people.”

Nizen Nijō Bosatsu Fu-sabutsu Ji, Never-Attaining Buddhahood by the Two Vehicles and Bodhisattvas in the Pre-Lotus Sūtras, Writings of Nichiren Shōnin,
Doctrine 3, Page 206-207

My disciples, think deeply! The countless bodhisattvas who had sprung up from underground were disciples of Lord Śākyamuni Buddha ever since the time He had first resolved to seek Buddhahood. Nevertheless, they neither came to see Him when He attained Buddhahood under the bodhi tree, nor visited Him when He passed away under the twin śāla trees. Thus, they may very well be accused of not being filial.

Moreover, they did not attend the preaching of the fourteen-chapter theoretical section, and they were absent when the last six chapters of the essential section were preached. They came and left while the first eight chapters of the essential section were being preached. But these great high-ranking bodhisattvas made a vow in the presence of Śākyamuni Buddha, the Buddha of Many Treasures and numerous Buddhas in manifestation that they would propagate the Five Characters transmitted to them at the beginning of the Latter Age of Degeneration. How can they not appear right now?

Kanjin Honzon-shō, A Treatise Revealing the Spiritual Contemplation and the Most Venerable One, Writings of Nichiren Shōnin, Doctrine 2, Page 160

[T]he Buddha of Many Treasures attested to the truth of the Lotus Sūtra (in the “Beholding the Stupa of Treasures” chapter), and the numerous Buddhas in manifestation coming from all the worlds in the universe verified the truthfulness of the sūtra by extending their long tongues to reach the Brahma Heaven (in the “Divine Powers of Buddhas” chapter). Thus the “three” Buddhas of Śākyamuni, the Buddha of Many Treasures, and the numerous Buddhas in manifestation verify the truth of the Lotus Sūtra. Therefore, we can say that while the Lotus Sūtra is one book, it is worth three books, its one phrase is worthy of three phrases, and one word is worthy of three words. That is to say, one written Chinese character in the Lotus Sūtra is equipped with the merits of these “three” Buddhas; it is like a wish-fulfilling gem. Regarding the wish-fulfilling gem, one equals a hundred. One gem produces immeasurable treasures while a hundred gems are also equipped with inexhaustible treasures. Suppose we grind a hundred kinds of herbs to make one or a hundred pills. Either one or one hundred, the pill has the same effect as the cure for an illness. This is like one drop of the ocean water being composed of the water of many rivers and one ocean includes the flavors of many rivers. Likewise, the Sūtra of the Lotus Flower of the Wonderful Dharma is a general term for the one book consisting of twenty-eight chapters and each of the twenty-eight chapters has a particular name. Gasshi (Yüeh-shih) is the general term for India, which is also called Gotenjiku (five regions of India). Japan is the general name for our country, and each of the sixty-six provinces of Japan has its own specific name.

Shijō Kingo-dono Gohenji, Response to Lord Shijō Kingo, Writings of Nichiren Shōnin, Followers I, Volume 6, Page 120

In their petition they also accuse Nichiren of being affixed solely to the Lotus Sūtra and slandering all other Mahāyāna sūtras. However, this is not my idea but the Buddha Himself declared in the Sūtra of Infinite Meaning, “The truth has not been revealed for forty years or so,” and in the Lotus Sūtra, “The truth will be expounded in this sūtra,” and “The truth will be revealed and expounded explicitly.” The Buddha of Many Treasures further attested to the truth by saying, “The teachings that have been expounded are all true.” Numerous Buddhas from all the worlds throughout the universe also approved these to be true by “touching the Brahma Heaven with their tongues.” Comparing the Lotus Sūtra with the sūtras that had been preached, are being preached, and will be preached, the Buddha only praised the Lotus Sūtra. So did other Buddhas. This is not my personal view. Besides, Grand Master Tokuitsu of the Hossō School in Nara tried to refute Grand Master Dengyō with the same criticism during the eras of Enryaku, Daidō, and Kōnin (782-824) and was defeated by Dengyō. As a result the Tendai Lotus School was established in Japan.

Gyōbin Sojō Goetsū, Understanding Gyōbin’s Petition, Writings of Nichiren Shōnin, Biography and Desciples, Volume 5, Page 6

Those who happen to know the difference between the true and evil teachings of the Buddha will be abandoned by all the people in the country. The protective deities of the land, without tasting the savior of the True Dharma, will lose their divine powers to benefit the people until in the end they will all abandon this country for some other lands. Taking advantage of the situation, evil demons will grow rampant throughout the land, causing the earth to quake, evil winds to blow, the entire country to suffer, and staple grains to fail to ripen. As a result a famine and water shortage will occur, evil devils will enter the bodies of the people to suck up their energy. This is called an epidemic. People all will lose the virtuous mind, and the majority of them will fall into evil realms. This solely stems from putting faith in provisional teachings preached by “evil friends.”

Shō Hokke Daimoku-shō, Treastise on Chanting the Daimoku of the Lotus Sūtra, Writings of Nichiren Shōnin, Faith and Practice, Volume 4, Page 13

It is most important for a man of wisdom to spread the Lotus Sūtra by keeping the difference of time in mind. For instance, for those who are thirsty, water is just what is necessary, not a bow and arrow or arms. What is needed for a naked person is clothing, not water. One can understand the overarching principle through this one example. If a fierce god spreads the Lotus Sūtra, you should donate your own flesh to him because a fierce god is fond of flesh. It is useless to donate clothing or other food to him. If an evil king tries to destroy the Lotus Sūtra, never obey his order even at the cost of life. When high priests who observe the precepts and are devoted to the pursuit of faith pretend to spread the Lotus Sūtra outwardly, but try to destroy it inwardly, you must reprimand them vigorously. The Lotus Sūtra, “Encouragement for Upholding This Sūtra” chapter, admonishes us to, “Solely to venerate the Supreme Way without sparing one’s own life.” It is preached in the Nirvana Sūtra, “Even at the cost of life, one should not conceal the king’s orders.” Grand Master Chang-an interprets this in his Annotation on the Nirvana Sūtra, “The reason why it is said that even at the cost of life one should not conceal the teaching is because life is not as important as the Dharma. We must spread the Dharma even at the cost of life.”

Hōren-shō, Letter to Hōren, Writings of Nichiren Shōnin,
Volume 6, Followers I, Page 60

Therefore, a practicer of the Lotus Sūtra who believes in the Lotus Sūtra and recites the daimoku has all the merit of the Buddha of Infinite Life and all other Buddhas throughout the universe without saying the nembutsu even once in his lifetime. It is like a wish-fulfilling gem equipped with all the treasures such as gold and silver.

Jisshō-shō, A Treatise on the Ten Chapters of the Great Concentration and Insight, Writings of Nichiren Shōnin, Doctrine 2, Page 6

Since this happened a long time ago when you were a child, you may not remember, but your late father was a warrior, whose duty was to kill people. However, as he wholeheartedly believed in the Lotus Sūtra, I know that he faced the last minutes of life peacefully. As the successor to your father, you too have been a strong believer in the Lotus Sūtra. How happy the soul of your father in his grave must be! How happy he would have been if he were alive!

The upholders of this sūtra, even if unrelated by blood, will meet on Mt. Sacred Eagle. How much more possible it is for you and your late father, faithful believers of the Lotus Sūtra, to be reborn on the same Mt. Sacred Eagle! You may regret that you lost your father while still young and were deprived of the privilege of receiving paternal guidance while other people enjoyed living together with their parents for 50 or 60 years, competing with one another for gray hair. When I think about the sorrow you must be feeling, I cannot stop shedding tears.

Ueno-dono Gohenji, Reply to Lord Ueno, Writings of Nichiren Shōnin, Volume 7, Followers II, Page 4

In the śrāvaka practice, there are ranks of wise men and sages, each of which is divided into seven levels. Those still within the seven levels of wise men are unenlightened.

Seven wise men (those who have knowledge)

• Three Wisdoms
  1. five ways to eliminate delusions
  2. to observe the four non-Buddhist misconceptions separately
  3. to observe the four non-Buddhist misconceptions all together
• Four Virtuous Roots
  1. to burn up evil passions
  2. to see clearly the law of cause and effect
  3. to realize the doctrine of the Four Noble Truths
  4. to be the wisest

Those who stay in the seven levels of Wise Men are wiser than the ordinary men of the Six Realms. Though they potentially have delusions and evil passions within themselves, they are wise men because they reject the delusions of life and death and suppress their evil passions. They are like the wise men Hsü-yu and Ch’ao-fu in ancient China mentioned in a non-Buddhist Chinese scripture. It is said that King Yao tried to appoint Hsü-yu to be the chief of the nine states, but thinking that his ears were defiled by hearing such a plan, Hsü-yu washed them in a river. Ch’ao-fu, who happened to hear the story just as he had brought his cows to drink from the river, stopped the cows from drinking the water.

Ichidai Shōgyō Tai-I, Outline of All the Holy Teachings of the Buddha, Writings of Nichiren Shōnin, Doctrine 3, Page 63

Now in the 11th Chapter of the Lotus Sutra, “Beholding the Stupa of Treasures,” a step was taken in preparation for revealing the Eternal Buddha in the sixteenth chapter on “The Life Span of the Buddha.” It is stated in the “Appearance of the Stupa of Treasures” chapter that Śākyamuni Buddha, who had attained enlightenment for the first time only forty years or so before under the bodhi tree at Buddhagayā, India, called the crowd of Buddhas, who had obtained Buddhahood as far before as a kalpa or ten, “My manifestations.” This was against the principle of equality among Buddhas and greatly surprised everyone. If Śākyamuni Buddha had attained enlightenment only forty years or so before, large crowds of people all over the universe would not be waiting for His guidance. Even if He was capable of appearing in manifestation to guide them in various worlds, it would have been of no use. Grand Master T’ien-t’ai said in his Profound Meaning of the Lotus Sūtra, fascicle 9, “Since there are so many of His manifestations, we should know that He has been the Buddha for a long time.” It represents the consternation of the great assembly, men and gods who were surprised at the great number of Buddhas in manifestation (funjin).

To add to their surprise, the numerous great bodhisattvas, who had been guided by the Original Buddha in the past, sprang out of the earth of the whole world, according to the “Appearance of Bodhisattvas from Underground,” the fifteenth chapter of the Lotus Sūtra. They looked incomparably superior to Bodhisattvas Fugen (Universal Sage) and Monju, (Mañjuśrī), who had been regarded as ranking disciples of Śākyamuni Buddha. Compared to these bodhisattvas coming from underground, those great bodhisattvas, who had gathered upon the preaching of the Flower Garland Sūtra, Hōdō sūtras, and Wisdom Sūtra and of the “Appearance of the Stupa Of Treasures” chapter of the Lotus Sūtra, or the sixteen bodhisattvas such as Bodhisattva Vajrasattva in the Great Sun Buddha Sūtra and other sūtras, looked like monkeys waiting on Indra or woodcutters associating with court nobles. Even Bodhisattva Maitreya, successor to Śākyamuni Buddha, did not know who they were, not to speak of gods and men below him.

Kaimoku-shō, Open Your Eyes to the Lotus Teaching, Writings of Nichiren Shōnin, Doctrine 2, Page 68