In the immemorable past, I must have been born a wicked king and must have deprived practicers of the Lotus Sūtra of their food and clothing and their properties on numerous occasions just as some people today in Japan have been destroying the Lotus temples. I must have also cut off the heads of numerous practicers of the Lotus Sūtra. I may have purged myself of some of these grave sins but not all of them. Even if I have, there are the residuals. In order to attain Buddhahood, I must completely compensate for all those serious sins. My merits in spreading the Lotus Sūtra are still shallow while my sins in the past are still deep. If I had preached only provisional sūtras, grave sins in my past lives would not have been revealed. It is like a forging iron, for instance. Unless you hit it and forge it hard, hidden scars will not be seen. They appear only when the iron is hit hard many times on an anvil. Or it is analogous to squeezing hemp seeds. Unless squeezed hard, there is little oil. Ever since I, Nichiren, strongly condemned those who slander the True Dharma in Japan, I have been persecuted. It must be that grave sins in my past lives are revealed through my merits in defending the dharma in this life. It is just as a piece of iron remains black unless heated by fire and becomes red when placed in fire. Even calm water makes great waves when quickly stirred by a log. A sleeping lion roars loudly when awakened by a touch of hand.

Kaimoku-shō, Open Your Eyes to the Lotus Teaching, Writings of Nichiren Shōnin, Doctrine 2, Page 107