Day 21 covers all of Chapter 16, The Duration of the Life of the Tathāgata.
Having last month concluded Chapter 16, The Duration of the Life of the Tathāgata, we begin again with Śākyamuni telling the congregation to pay attention.
Thereupon the Buddha aid to the great multitude including Bodhisattvas and others, “Good men! Understand my sincere and infallible words by faith!”
He said to the great multitude again, “Understand my sincere and infallible words by faith!”He said to them once again, “Understand my sincere and infallible words by faith!”
Thereupon the great multitude of Bodhisattvas, headed by Maitreya, joined their hands together and said to the Buddha, “World-Honor done, tell us! We will receive your words by faith.”
They said this three times. Then they said once again, “Tell us! We will receive your words by faith.”
Thereupon the World-Honored One, seeing that they repeated their appeal even after they repeated it three times, said to them:
“Listen to me attentively! I will tell you about my hidden core and supernatural powers. The gods, men and asuras in the world think that I, Śākyamuni Buddha, left the palace of the Śākyas, sat at the place of enlightenment not far from the City of Gayā, and attained Anuttara-samyak-saṃbodhi [forty and odd years ago]. To tell the truth, good men, it is many hundreds of thousands of billions of nayutas of kalpas since I became the Buddha. Suppose someone smashed into dust five hundred thousand billion nayuta asaṃkhya worlds, which were each composed of one thousand million Sumeru-worlds, and went to the east [carrying the dust with him). When he reached a world at a distance of five hundred thousand billion nayuta asaṃkhya worlds [from this world], he put a particle of dust on that world. Then he went on again to the east, and repeated the putting of a particle of the dust [on the world at every distance of five hundred thousand billion nayuta asaṃkhya worlds] until the particles of the dust were exhausted. Good men! What do you think of this? Do you think that the number of the world he went through is conceivable, countable, or not?”
Maitreya Bodhisattva and others said to the Buddha:
“World-Honored One! Those worlds are innumerable, uncountable, inconceivable. No Śrāvaka or Pratyekabuddha could count them even by his wisdom-without-āsravas. We are now in the state of avaivartika, but cannot, either. World-Honored One! Those worlds are innumerable.”
Thereupon the Buddha said to the great multitude of Bodhisattvas:
“Good Men! Now I will tell you clearly. Suppose those worlds, whether they were marked with the particles of the dust or not, were smashed into dust. The number of the kalpas which have elapsed since I became the Buddha is on hundred thousand billion nayuta asaṃkhyas larger than the number of the particles of the dust thus produced. All this time I have been living in this Sahā-World, and teaching [the living beings of this world] by expounding the Dharma to them. I also have been leading and benefiting the living beings of one hundred thousand billion nayuta asaṃkhya worlds outside this world.
Nichiren comments on what happened when the Eternal Buddha was revealed in his letter, A Treatise :Revealing the Spiritual Contemplation and the Most Verable One:
[W]hen the Eternal Buddha was revealed in the essential section of the Lotus Sūtra, this world of endurance (Sahā World) became the Eternal Pure Land, indestructible even by the three calamities of conflagration, flooding, and strong winds, which are said to destroy the world. It transcends the four periods of cosmic change: the kalpa of construction, continuance, destruction, and emptiness. Śākyamuni Buddha, the Lord-preacher of this Pure Land, has never died in the past, nor will He be born in the future. He exists forever throughout the past, present, and future. All those who receive His guidance are one with this Eternal Buddha. It is because each of our minds is equipped with the “3,000 modes of existence” and the “three factors,” namely, all living beings, the land in which they live, and the five elements of living beings (matter, perception, conception, volition and consciousness).
This truth was not made clear in the first fourteen chapters of the theoretical section of the Lotus Sūtra. Perhaps it was because the time was not ripe at this stage of preaching the Lotus Sūtra; and capacity of comprehension on the part of the listeners was not yet sufficient.
Kanjin Honzon-shō, A Treatise Revealing the Spiritual Contemplation and the Most Verable One, Writings of Nichiren Shōnin, Doctrine 2, Page 148