The Lotus Sūtra enjoins us to give up the provisional teachings, saying that with faith we can enter the Way to Buddhahood. The Nirvana Sūtra preached last in the śāla forest states that there are numerous ways to get the seed of Buddhahood, but as faith in the Three Treasures include all those ways, it is faith in the Three Treasures that matters most. The basic way to Buddhahood thus lies in faith.

Hokke Daimoku Shō, Treatise on the Daimoku of the Lotus Sūtra, Writings of Nichiren Shōnin, Faith and Practice, Volume 4, Page 36-37

How can we identify the sage of the Lotus Sūtra in the Latter Age of Degeneration? The Lotus Sūtra states, “He who preaches this sūtra to others and can uphold it for himself is a messenger of the Buddha.” In other words, anyone who recites eight chapters of the Lotus Sūtra, or one fascicle, one chapter, or just a verse of it, or chants the daimoku is a messenger of the Buddha. He who carries through faith in the Lotus Sūtra to the end, enduring the great persecutions that arise, is the true messenger of the Buddha.

Shijō Kingo-dono Gohenji, Response to Lord Shijō Kingo, Writings of Nichiren Shōnin, Followers I, Volume 6, Page 153

The moon does not reflect on dirty water, and birds do not build nests in dead trees. Likewise, Śākyamuni Buddha does not reside in the body of a woman without faith. However, a woman who believes in the Lotus Sūtra is like a body of pure water. The moon, Śākyamuni Buddha, reflects upon it.

To put it figuratively, a woman can’t feel her pregnancy in the beginning, but after a while she begins to suspect it until she knows for sure that she is pregnant. An attentive woman can even tell whether she has conceived a boy or a girl.

The same could be said about the doctrines of the Lotus Sutra. If we believe in the merit of “Namu Myōhō Renge Kyō,” Śākyamuni Buddha will be conceived in our hearts before we know it, just as a woman is pregnant before she knows it. We can’t feel it in the beginning, but as the months pass we begin dreaming of the Buddha residing in our hearts, until we feel happiness within us. There are many doctrines, but I will stop talking about them for now.

Matsuno-dono Nyōbō Go-henji, A Response to the Wife of Lord Matsuno, Nyonin Gosho, Letters Addressed to Female Followers, Page 242-244

Endeavor to strengthen your faith after listening to this important teaching. He who endeavors to strengthen his faith after listening to the teaching of the Lotus Sūtra is a true seeker of Buddhahood. Grand Master T’ien-t’ai says: “Indigo becomes deep blue even though it is created from indigo leaves.” This means that if dyed blue over and over, indigo blue will become deeper than its original color. Practicing the Lotus Sūtra is the same. By practicing the teaching of the Lotus Sūtra over and over, you will be a true follower. Practice is the best master.

Ueno-dono Goke-ama Go-henji, A Response to the Nun, Widow of Lord Ueno, Nyonin Gosho, Letters Addressed to Female Followers, Page 48-50

QUESTION: Suppose ordinary people, priests or lay persons, uphold, read and write or let others read and write the entire Lotus Sūtra without understanding its meaning. Or perhaps they focus on just one of its fascicles, or the four important chapters (chapters 2, 14, 16 and 25), or even just the verse at the end of the “Life Span of the Buddha” chapter without fully appreciating the depth of the sūtra. Suppose there are people who, though they do not read and write the sūtra themselves, show respect by pressing their palms together in the form of gasshō, bow in front of it, offer incense and flowers to it. Or suppose there are people who, though they do not practice these things themselves, are happy seeing others perform such practices, and rejoice that this sūtra is spreading all over the country. Can such people, due to their own merit of having practiced a little, avoid committing worldly sins and be reborn in the realms of human and heavenly beings just as Hinayana sages on the first stage of sainthood are always reborn in the realms of humans and gods without falling into the three evil realms (hell, realm of hungry souls and that of beasts and birds)? Can they in the end perceive the Lotus Sūtra or be reborn in the Pure Lands all over the universe or become Buddhas with their present bodies? I would like to hear about this in detail.

ANSWER: Though my understanding of the sūtra is not profound, as I contemplate the spirit of the Lotus Sūtra and the Nirvana Sūtra, as well as their interpretations by T’ien-t’ai and Miao-lê, it seems to me that those who possess even the slightest belief in the Lotus Sūtra without holding any enmity against its teaching will not fall into the evil realms even if they commit evil deeds.

Shō Hokke Daimoku-shō, Treastise on Chanting the Daimoku of the Lotus Sūtra, Writings of Nichiren Shōnin, Faith and Practice, Volume 4, Page 1-2

[T]he sin of not believing in and slandering the Lotus Sūtra is explained in detail in the “Parable” chapter. The sin of slandering the upholders of the Lotus Sūtra is preached in the “Teacher of the Dharma” chapter. The merits of those who believe in the Lotus Sūtra is expounded in the “Variety of Merits” and “Merits of Rejoicing at Hearing This Sūtra” chapters. Slandering the dharma means going against the teaching and rejoicing at hearing the dharma means to be obedient to the teaching. Do you think those who understand the preciousness of the Lotus Sūtra even for a moment without quite understanding its meaning are going against the teaching or being obedient to it? Aren’t the merits of ignorant people in the Latter Age of Degeneration holding a religious service in honor of or rejoicing at hearing the Lotus Sūtra even for a moment preached in scriptures? Besides, according to the interpretations of T’ien-t’ai and Miao-lê, it was an act of slandering the True Dharma when Buddhist masters of other schools regarded such Lotus practices as a child building a sand Stupa for play, rejoicing at hearing a verse or phrase of the sūtra, or the person rejoicing at hearing the sūtra equal to the practices for sages and wise people preached in the pre-Lotus sūtras.

Shō Hokke Daimoku-shō, Treastise on Chanting the Daimoku of the Lotus Sūtra, Writings of Nichiren Shōnin, Faith and Practice, Volume 4, Page 7

Examining many sūtras, we thus see they all regard slandering the True Dharma the most serious crime. How sad it is that people [in Japan] all should wander out of the gate of the True Dharma into the prison of evil dharma! Such ignorance is causing everyone [in Japan, high and low,] to be pulled by the rope of evil teachings and caught forever by the net of slandering the True Dharma! In this life such wanderers are lost in the mist of delusions; in the next life they will sink to the bottom of flaming hell. How sad it is! How terrible it is!

You should promptly discard your false faith and take up the true and sole teaching of the Lotus Sūtra at once. Then this triple world of the unenlightened will all become Buddha lands. Will Buddha lands ever decay? All the worlds in the universe will become Pure Lands. Will Pure Lands ever be destroyed? When our country does not decay and the world is not destroyed, our bodies will be safe and our hearts tranquil. Believe these words and revere them!

Risshō Ankoku-ron, Treatise on Spreading Peace Throughout the Country by Establishing the True Dharma, Writings of Nichiren Shōnin, Doctrine 1, Pages 141-142

The reason why such śrāvaka disciples as Śāripūtra and Maudgalyāyana were in the Hell of Incessant Suffering for as long as 3,000 or 500 (million) dust-particle kalpa was not because they committed the crime of ten evil acts, five rebellious sins, or eight rebellious sins such as treason. It was simply because they met “evil friends,” abandoned the faith in the Lotus Sūtra, and moved to the faith in the expedient teachings. Grand Master T’ien-t’ai explains this in his Profound Meaning of the Lotus Sūtra, fascicle 6, “Upon meeting an ‘evil friend,’ people lose their right mind.” The right mind refers to the mind of putting faith in the Lotus Sūtra, and losing the right mind means abandoning the faith in the Lotus Sūtra and putting faith in other sūtras. Therefore, it is preached in the Lotus Sūtra, “The Life Span of the Buddha” chapter, “No matter how effective a medicine is, such a person will never take it.” This is explained by Grand Master T’ien-ta’i in his Profound Meaning of the Lotus Sūtra, fascicle 6, “A person who has lost his right mind will not take a good medicine, no matter how effective it is, choosing instead to roam about the street of life and death, and run away to foreign countries.”

Kyōdai-shō, A Letter to the Ikegami Brothers, Writings of Nichiren Shōnin, Volume 6, Followers I, Page 75

Of the people who put faith in the Lotus Sūtra today, some have faith like fire while others have it like water. Those who have faith like fire refer to those who become enthusiastic upon listening to the preaching but their passion cools down as times goes by, and eventually forget the teaching. On the other hand, those whose faith is like water mean those whose faith is like a ceaselessly flowing water, namely those who retain their faith without retreating.

Ueno-dono Gohenji, A Reply to Lord Ueno, Writings of Nichiren Shōnin, Faith and Practice, Volume 4, Page 126