The reason why those who had received the seed of Buddhahood in the eternal past have been transmigrating the six realms (lower states of existence) ever since for as long as “500 dust-particle kalpa” without attaining Buddhahood, and those who had heard the Lotus Sūtra at the time of the Great Universal Wisdom Buddha have been undergoing transmigration in the six realms ever since for the “3,000 dust-particle kalpa” was because they abandoned the great teaching of the Lotus, seeking refuge instead in expedient and Hinayāna sūtras preached forty years or so before the Lotus Sūtra. Later they gave up faith in those expedient sūtras, too, and thus have continued to transmigrate through the six realms.

Shugo Kokka-ron, Treatise on Protecting the Nation, Writings of Nichiren Shōnin, Doctrine 1, Page 42

The Lotus Sūtra, fascicle 5 (15th chapter on “The Appearance of Bodhisattvas from Underground”) preaches, “I have always taught them in their past existence… , and as soon as they saw Me and heard My preaching in this life, they received My teachings by faith, entering into the wisdom of the Buddha.” Interpreting this, Grand Master T’ien-t’ai states in his Words and Phrases of the Lotus Sūtra, “People today were taught and received the seed of Buddhahood in the eternal past.” Grand Master Miao-lê, on the other hand, declares in his Annotations on the Words and Phrases of the Lotus Sūtra, “Although it is in the present when people gain the benefit of attaining Buddhahood, the seed of Buddhahood was sown in the eternal past,” and in his Commentary on the Profound Meaning of the Lotus Sūtra, “Thus I know that the preaching of Śākyamuni Buddha today is for those in whom the seed of Buddhahood was sown in a past existence.” I do not have to explain what is said in the sūtra and its annotations, which are very clear in meaning.

Soya Nyūdō-dono-gari Gosho, A Letter to Lay Priest Lord Soya, Writings of Nichiren Shōnin, Doctrine 3, Pages 150.

A man of shallow faith pretends to have right faith and is contemptuous towards other followers, so as to harm the faith of others. Leave such people alone.

Ueno-dono Gohenji, A Reply to Lord Ueno, Writings of Nichiren Shōnin, Faith and Practice, Volume 4, Page 112

Those who had neither a chance to hear the Lotus teaching in the past nor the intention of putting faith in the Lotus Sūtra in this life will fall into evil realms anyway. Therefore, they should be forced to hear the Lotus Sūtra, causing them to slander the sūtra, which eventually enables them to attain Buddhahood in the future through the merit of reverse relationship.

Shō Hokke Daimoku-shō, Treastise on Chanting the Daimoku of the Lotus Sūtra, Writings of Nichiren Shōnin, Faith and Practice, Volume 4, Page 22

Now we live in a Latter Age. People are not saints, astray in a dark alley leading to hell, and are forgetting all about the direct route to Buddhahood. How sad it is that no one awakens them! What a pity it is that only false faith grows rampant!

Risshō Ankoku-ron, Treatise on Spreading Peace Throughout the Country by Establishing the True Dharma, Writings of Nichiren Shōnin, Doctrine 1, Page 122

I received your letter, in which you said that you used to chant one chapter of the Lotus Sūtra each day, taking twenty-eight days to finish chanting it once; and that recently, however, you chant only the “Previous Life of the Medicine-King Bodhisattva” chapter each day. Then you asked: “Should I chant each chapter each day as I used to?”

You may chant the whole twenty-eight chapters, one chapter, one paragraph, one sentence or even one character of the Lotus Sūtra a day. Or, you may chant the daimoku, “Namu Myōhō Renge Kyō,” just once in a day or once in your whole life. Even if you may never chant the daimoku yourself, you may rejoice at hearing others chant it just once in your whole life. Or you may rejoice with others who rejoice at hearing a voice chanting the daimoku. The joy of the daimoku chanting transmitted 50 times this way from person to person, will grow weaker steadily until in the last fiftieth person it will be as uncertain as the mind of a two- or three-year-old baby or as unpredictable as a horse or a cow, which cannot tell the difference between head and tail. Nevertheless, the merit of such people is one hundred thousand billion times greater than that of those whose wisdom is as great as Śāriputra, Maudgalyāyana, Mañjuśrī, and Maitreya, but put faith in sūtras other than the Lotus Sūtra and memorize them all.

This is explained in the chapter on the “Merits of a Person Who Rejoices at Hearing This Sūtra” of the Lotus Sūtra as well as in the 60-volume works of Grand Masters T’ien-t’ai and Miao-lê. The Lotus Sūtra states also that even the Buddha cannot measure the merit of those who put faith in even one character or sentence of the Lotus Sūtra. The Buddha has boundless wisdom; He can measure the amount of rain that has continued to fall for one or two weeks in the whole universe. Nevertheless, He cannot measure the merit of those who chant just one character or phrase of the Lotus Sūtra. How can we, sinners and the ignorant, measure this merit?

Regardless, very few people believe in the Lotus Sūtra, which is worthy of such great merit.

Gassui Gasho, A Letter on Menstruation, Nyonin Gosho, Letters Addressed to Female Followers, Page 22-24

It is stated in the Lotus Sūtra, fascicle 2, chapter 3 on “A Parable,” “If a person does not believe in but slanders this sutra, he will immediately destroy all the seeds for attaining Buddhahood in this world.” It is because one aspect of having no faith in this sūtra causes others to abandon the Lotus Sūtra. Interpreting this, Bodhisattva Vasubandhu, therefore, states in the first fascicle of his Treatise on the Buddha-nature, “He who hates and contradicts Mahāyāna becomes an icchantika (one who has no goodness in his nature and therefore, no possibility of attaining Buddhahood) because such a person causes people to abandon this dharma.”

Shugo Kokka-ron, Treatise on Protecting the Nation, Writings of Nichiren Shōnin, Doctrine 1, Page 30-31

QUESTION: Do you have scriptural proof that even those who believe without comprehension can attain Buddhahood?

ANSWER: The Nirvana Sūtra, fascicle 32, states, “There are many causes of attaining Buddhahood; faith, however, is all-inclusive.” Fascicle 9 in the same sūtra also preaches, “Upon hearing this sūtra, everything becomes the cause and by-cause of attaining enlightenment. The Buddha’s voice of preaching and rays of light emitted by the Buddha all enter through pores necessarily enabling listeners to attain enlightenment.” And the Lotus Sūtra, chapter 3 on the “Parable,” preaches that one can “gain entrance to Buddhahood through faith alone.”

Ken Hōbō-shō, A Clarificaton of Slandering the True Dharma, Writings of Nichiren Shōnin, Doctrine 3, Pages 136.