QUESTION: Is there any scriptural proof that we gain merits through the exclusive chanting of the daimoku?
ANSWER: The Lotus Sūtra says in chapter 26, “Dhārāṇi,” of the 8th fascicle that the merits obtained will be immeasurable when one keeps only the name of the Lotus Sūtra. The Lotus Sūtra of the True Dharma says in the chapter of “Total Upholding” that the merits of a person who hears this sūtra and keeps its name will be innumerable. The Lotus Sūtra with Additions says in the chapter of “Dhārāṇi” that the merits will be innumerably great when one keeps the name of the Lotus Sūtra. These clearly show how great the merits are for those who chant the daimoku.
Hokke Daimoku Shō, Treatise on the Daimoku of the Lotus Sūtra, Writings of Nichiren Shōnin, Faith and Practice, Volume 4, Page 39