Since the Great Concentration and Insight preaches the way of practicing the spiritual contemplation according to the doctrine of “3,000 existences in one thought” in the Lotus Sūtra, the way to practice the “threefold contemplation in a single thought” is nothing but recognizing the Wonderful Dharma to be beyond conceptual understanding. Therefore, the priests who belittle the Lotus Sūtra and make too much of the spiritual contemplation commit the grave sin of slandering the True Dharma, are men of false view, or are as devilish as a heavenly devil. This is because according to Grand Master T’ien-t’ai’s “threefold contemplation in a single thought, concentration and insight” means the unique state of mind in which one is enlightened with the truth of One Buddha teaching through steadily maintaining the mind in tranquility by the Lotus Sūtra.

Risshō Kanjō, A Treatise on Establishing the Right Way of Meditation, Writings of Nichiren Shōnin, Doctrine 2, Page 219