Because I am deeply concerned about you I would like to tell you another important story. During the time of Yin in ancient China, the King of Ku-chu State had two princes named Pê-i and Shu-ch’i. The King chose the younger brother Shuch’i as his successor, but Shu-ch’i refused to ascend the throne upon the death of the King. Pê-i advised the younger brother to accede to the throne, but Shu-ch’i insisted that the elder brother should succeed the father. Pê-i protested saying, “How can we go against the will of our father?” Shu-ch’i retorted, “I understand the will of our father; however, how can I ascend the throne, disregarding my elder brother?” In the end, respecting the views of the other, both Pê-i and Shu-ch’i left the state of their parents and went to a foreign land.

While both brothers were serving King Wen of Chou, King Wen was murdered by King Chou Hsin of Yin, and King Wu of Chou, son of King Wen, started a war against King Chou Hsin of Yin within 100 days after the death of his father. Pê-i and Shu-ch’i held fast to King Wu’s horse, remonstrating the King saying, “Isn’t it unfilial to begin a war within three years after the passing of parents?” King Wu became furious and tried to kill Pê-i and Shu-ch’i, but they were spared when T’ai-kung Wang interceded.

The two brothers left the service of King Wu, and hid themselves in Mt. Shou-yang, staying alive by eating bracken. One day they came across a person called Wang Ma-tzŭ and told him the reason why they were hiding in the mountain. Wang Ma-tzŭ then reproached them saying, “Isn’t the bracken owned by King Wu of Chou?” Accused by Wang Ma-tzŭ, the two brothers stopped eating bracken. As it is the custom in heaven not to abandon a sage, heaven appeared as a white deer and fed the two brothers with its milk. One day Shu-ch’i casually remarked, “The milk of this white deer is very tasty, let alone its meat.” Although Pê-i stopped him from saying anything more, heaven heard it. As a result the white deer never appeared again and the two brothers died of hunger. In this way, even a person who lived as a sage throughout his life might destroy himself with one word.

Kyōdai-shō, Letter to the Ikegami Brothers, Writings of Nichiren Shōnin, Volume 6, Followers I, Page 79

The lives of sages, protected by the gods, lost with an inappropriate jest.

The tales Nichiren uses to illustrate his letters always intrigue me. This letter was sent to the Ikegami brothers, Munenaka and Munenaga, and their wives. Their faith in the Lotus Sūtra was being challenged by their father. The moral of this tale is used in a later letter addressed to the younger brother, Munenaga:

It is true that a bale of karukaya grass saved for 1,000 years burns to ashes in a flash and the merits of achievement gained in one hundred years can be wasted in one word.

Hyōesakan-dono Gohenji, Answer to Lord Ikegami Munenaga, Writings of Nichiren Shōnin, Volume 6, Followers I, Page 92