Rivers come together to form an ocean. Particles of dust accumulate to become Mt. Sumeru. When I, Nichiren, began having faith in the Lotus Sūtra, it was like a drop of water or a particle of dust in Japan. However, when the sūtra is chanted and transmitted to two, three, ten, a million, and a billion people, it will grow to be a Mt. Sumeru of perfect enlightenment or the great ocean of Nirvana. There is no way other than this to reach Buddhahood.
Senji-shō, Selecting the Right time: A Tract by Nichiren, the Buddha’s Disciple, Writings of Nichiren Shōnin, Doctrine 1, Page 243-244