Day 30 covers all of Chapter 26, Dhāraṇīs
Having last month received Brave-In-Giving Bodhisattva’s dhārāni spells, we receive Vaiśravaṇa Heavenly-King’s dhārāni spells.
Thereupon Vaiśravaṇa Heavenly-King, the Protector of the World, said to the Buddha, “World-Honored One! I also will utter dhārānis in order to protect this teacher of the Dharma out of my compassion towards all living beings.”
Then he uttered spells, “Ari (1), nari (2), tonari (3), anaro (4), nabi (5), kunabi (6).”
[He said to the Buddha:]
“World-Honored One! I will protect this teacher of the Dharma with these divine spells. I also will protect the person who keeps this sūtra so that he may have no trouble within a hundred yojanas’ distance [from here].”
The significance of Vaiśravaṇa Heavenly-King’s dhārāni spells is outlined in a letter by Nichiren:
It has been 2,200 years or so since the Buddha expounded the Lotus Sūtra. As the life span of human beings is short, there is no one still alive who was able to see the Buddha in person. The length of a day as well as the life span in the realm of heavenly beings, however, are so long that there exist numerous heavenly beings who listened to the Buddha preach the Lotus Sūtra. Fifty years for human beings is equivalent to one day and night for the Four Heavenly Kings. Passing the day and night in this way, with 30 days in a month and 12 months to a year they live altogether 500 years. Accordingly, 2,200 years or so in the human realm is equivalent to 44 days of the Four Heavenly Kings, and it has been only 44 days since the sun and moon and Vaiśravaṇa (Bishamon, one of the Four Heavenly Kings) saw the Buddha enter Nirvana. In other words, it has not been two months yet since the Buddha passed away. To such heavenly beings as Indra and the King of the Brahma Heaven it has been a month or so since the Buddha passed into Nirvana. How can they forget all about the vow they made before the Buddha, the great favor of the sūtra in which they attained Buddhahood, and abandon the practicers of the Lotus Sūtra in such a short span? When we think of things in this way, we are sure we can depend on these heavenly beings.
Kitō Shō, Treatise on Prayers, Writings of Nichiren Shōnin, Faith and Practice, Volume 4, Page 62-63