The wise do not forget times of distress, even though they may be in times of peace and tranquility. The foolish, on the other hand, do not realize approaching danger and continue to enjoy living in comfort. It is said that a great fire fears a small amount of water, and a large tree pays attention to a small bird so that its twigs will not be broken off. Likewise, wise persons are always cautious not to slander the Mahāyāna teachings. Consequently, in the event such an offense is committed, Bodhisattva Vasubandhu vowed to cut off his tongue; Bodhisattva Aśvaghoṣa said he would behead himself. Moreover, Grand Master Chi-ts’ang served Grand Master T’ien-t’ai as a stepladder; Tripitaka Master Hsüan-chuang made a trip to India, the land of the Buddha, in search of the Dharma; Tripiṭaka Master Amoghavajra went to India in order to resolve his doubt; and Grand Master Dengyō went abroad to China to master the Dharma. They thus risked their lives in order to clarify the truth of the Buddhist Dharma and to uphold it.

Toki-dono Gosho, A Letter to Lord Toki, Writings of Nichiren Shōnin, Faith and Practice, Volume 4, Page 117