Fascicle nine of the Words and Phrases of the Lotus Sūtra says, “The beginner is afraid that getting drawn into the myriad activities that are supporting conditions will hinder their practice of right action. At this time, they should solely uphold this sūtra which is the best kind of offering. By dispensing with other matters in order to uphold the principle they will gain enormous benefit.”

This commentary says that the supporting conditions are the first five of the six bodhisattva practices. A beginner who tries to practice them as well will hinder his own right action of faith. For instance, if a small boat overloaded with treasure tries to cross the ocean, both the boat and the treasure will sink. The phrase “solely uphold this sūtra” does not even refer to the whole sūtra but only to upholding the daimoku, not any other passages. If even reading and writing the whole sūtra is not allowed, then still less (should a beginner attempt to practice) the first five bodhisattva practices.

The phrase, “dispensing with other matters in order to uphold the principle” means to give up the observation of the precepts and other matters and only practice the daimoku, which is the principle. “They will gain enormous benefit” means, conversely, that a beginner who tries to practice everything else and the daimoku at the same time will lose all the benefits of their practice.

Shishin Gohon-shō, The Four Depths of Faith and Five Stages of Practice, Writings of Nichiren Shōnin, Faith and Practice, Volume 4, Page 105