Day 15 completes Chapter 10, The Teacher and the Dharma, and introduces Chapter 11, Beholding the Stupa of Treasures.

The Buddha explains that the Lotus Sutra “is the most difficult to believe and the most difficult to understand” because it is “the store of the hidden core of all the Buddhas.”

Medicine-King, know this! Anyone who copies, keeps, reads and recites this sūtra, makes offerings to it, and expounds it to others after my extinction, will be covered by my robe. He also will be protected by the present Buddhas of the other worlds. He will have the great power of faith, the power of vows, and the power of roots of good. Know this! He will live with me. I will pat him on the head.

Living with the Buddha, covered in his robe.

Without the Lotus Sutra?

Medicine-King! Although many laymen or monks will practice the Way of Bodhisattvas, they will not be able to practice it satisfactorily, know this, unless they see, hear, read, recite, copy or keep this Sūtra of the Lotus Flower of the Wonderful Dharma or make offerings to it. If they hear this sūtra, they will. Anyone who, while seeking the enlightenment of the Buddha, sees or hears this Sūtra of the Lotus Flower of the Wonderful Dharma, and after hearing it, understands it by faith and keeps it, know this, will approach Anuttara-samyak-saṃbodhi.

And…

A man on a plateau, feeling thirsty,
Dug a hole in order to get water.
As long as he saw the dug-out lumps of earth were dry,
He knew that water was still far off.
When he found the earth wet and muddy,
He was convinced that water was near.

In the same manner, Medicine-King, know this!
Those who do not hear
The Sūtra of the Lotus Flower of the Wonderful Dharma
Are far from the wisdom of the Buddha.

What is required to expound the Lotus Sutra?

Medicine-King! How should the good men or women who live after my extinction expound this Sūtra of the Lotus Flower of the Wonderful Dharma to the four kinds of devotees when they wish to? They should enter the room of the Tathāgata, wear the robe of the Tathāgata, sit on the seat of the Tathāgata, and then expound this sūtra to the four kinds of devotees. To enter the room of the Tathāgata means to have great compassion towards all living beings. To wear the robe of the Tathāgata means to be gentle and patient. To sit on the seat of the Tathāgata means to see the voidness of all things.

And then suddenly, without warning, a giant stupa of treasures rises from the earth and hangs in the air and from inside a loud voice is heard to say:

“Excellent, excellent! You, Śākyamuni, the World-Honored One, have expounded to this great multitude the Sūtra of the Lotus Flower of the Wonderful Dharma, the Teaching of Equality, the Great Wisdom, the Dharma for Bodhisattvas, the Dharma Upheld by the Buddhas. So it is, so it is. What you, Śākyamuni, the World-Honored One, have expounded is all true.”