The Buddha is a perfected being with a human personality. He is the ideal toward which all human beings strive. It had long been believed that to become such a perfect being takes an endlessly long period of training and practice. But [in Chapter 12, Devadatta,] the daughter of the Dragon-King attained enlightenment quickly. Her case is called, “The Attainment of Buddhahood in This Very Life.” It maintains that ordinary people have the possibility to attain enlightenment in their own bodies (during their present lifetimes), and teaches that the Buddha’s power works within the bodies of ordinary people. The idea of “the attainment of Buddhahood in this life” greatly influenced Japanese society after the Great Master Dengyo introduced it from China in 805. Dengyo, a Japanese scholar, had already read about it in the Lotus Sutra, but he found that the Chinese had worked it out in detail. Also, Nichiren explained this idea in Kanjin-honzon-sho (“A Treatise Revealing the Spiritual Contemplation of the Most-Venerable-One”). In it he says, “Sakyamuni Buddha, who has attained Perfect Enlightenment, is our flesh and blood, and all the merits he has accumulated before and after attaining Buddhahood are our bones.”
Introduction to the Lotus Sutra