You should consider that the Lotus Sūtra is like the king, parents, sun and moon, great ocean, Mt. Sumeru and heaven and earth while other sūtras are like regents, ministers, court nobles, or all the people in the country, various stars, rivers, mountains, trees and plants. We are the ignorant in the Latter Age of Degeneration committing sins and are not capable of accepting the Dharma. The king helps the people rather than his retainers; parents have compassion on their own children more so than unrelated persons; and the light of the sun and the moon is brighter than stars. Likewise, if the Lotus Sūtra is unsuitable to save the ignorant with inferior capacity in the Latter Age of Degeneration, you should realize there is no other sūtra.

Shō Hokke Daimoku-shō, Treastise on Chanting the Daimoku of the Lotus Sūtra, Writings of Nichiren Shōnin, Faith and Practice, Volume 4, Page 14