Yoshiro Tamura: Emissaries of the Tathagata,

Nichiren was especially attracted to the term “apostle” or “emissary” of the Tathagata, which appears [in chapter 10]. Influenced by this term, Nichiren used the phrase “follower of the Lotus Sutra.” The Lotus Sutra says, in connection to the phrase “emissaries of the Tathagata,” that those who devote themselves to embodying the truth in this world even a little are people who have been sent from the pure world of the Buddha to be born in this world because they have compassion for people. This suggests a meaning or purpose for being born in this world. Nichiren was able to gain courage and meaning for living from this kind of phrase, despite having to bear much suffering.

Yoshiro Tamura, "Introduction to the Lotus Sutra", p76