The use of the terms “eternity, joy, self and purity” by non-Buddhists in India were wrong in meaning, but they were so good as names that the Buddha used them to name the four kinds of virtues of Nirvana in Mahāyāna Buddhism later. However, the Buddha hated these terms at first in order to get rid of the non-Buddhist ideas. Even evil is the seed of Buddhahood, and so is virtue. Although the principle of emptiness to which śrāvaka and pratyekabuddha were stuck was virtuous, not evil at all, the Buddha reproached them in order to break their adherence to it. The nembutsu today destroys the Lotus Sūtra in this country. Therefore, the nembutsu must be denied and criticized even though it is good and not wrong in meaning for the sake of the Lotus Sūtra. It is because in Buddhism there is a suitable dharma for each country.

Jisshō-shō, A Treatise on the Ten Chapters of the Great Concentration and Insight, Writings of Nichiren Shōnin, Doctrine 2, Page 5