This letter, written at Minobu in 1277, is entitled The Workings of Brahmā and Shakra, because it contains the passage, “The time will certainly come when, by the workings of Brahmā, Shakra, and other gods, the entire Japanese nation will simultaneously take faith in the Lotus Sutra.” In this letter Nichiren Daishonin encourages the nineteen-year-old Nanjō Tokimitsu, who succeeded his father as steward of Ueno Village in Fuji District of Suruga Province, to maintain his faith. He also advises Tokimitsu on how to respond to those who attempt to threaten or deceive him into discarding his faith. For if they succeed in their attempt, the Daishonin warns, they will use him “as a means for making many others abandon their faith.”

https://www.nichirenlibrary.org/en/wnd-1/Content/96