The reason why we continue to transmigrate through the six lower realms without attaining Buddhahood from the eternal past of innumerable kalpa (aeons) till today is that we fail to give up our lives for the sake of the Lotus Sūtra. Gladly Seen Bodhisattva burned himself for 1,200 years as a votive light to the Sun Moon Pure Bright Virtue Buddha and burned his arms for 72,000 years to the Lotus Sūtra. He is Medicine King Bodhisattva today. Never Despising Bodhisattva was abused, disparaged, beaten with sticks and rubble was thrown at him for many kalpa (aeons) in order to disseminate the teaching of the Lotus Sūtra. Did he not become Śākyamuni Buddha in a future existence? Therefore, the way of practicing the sūtra leading to Buddhahood differs according to the times.

Ichinosawa Nyūdō Gosho, A Letter to Lay Priest Ichinosawa, Writings of Nichiren Shōnin, Volume 6, Followers I, Page 162