The Great Concentration and Insight also lists the six causes of sickness: 1. lack of harmony among the four constituent elements of the material world (the earth element, the water element, the fire element and the wind element); 2. lack of moderation in eating and drinking; 3. inconsistent practice of sitting meditation; 4. problems caused by a demon; 5. actions of a heavenly demon; and 6. karmic retribution. It is preached in the Sūtra on the Great Extinction, “There are three categories of people with illness who are difficult to heal: in the first place are those who slandered the Mahāyāna sūtras; in the second place are those who committed the five rebellious sins; and in the third place are icchantika (those who do not have goodness in mind and therefore have no possibility of attaining Buddhahood). These three kinds of illnesses are the most serious of all types of diseases in the world.” The Nirvana Sūtra also preaches, “If one commits an evil act in this world, one will inevitably go to hell in the next world. However, if one gives offerings to the Three Treasures (Buddha, Dharma, and Saṃgha), one will receive a lighter form of retribution such as headaches, sore eyes, and backaches in this world instead of going to hell in the next world.” Interpreting this, the Great Concentration and Insight states, “Even if one committed a serious sin, for which one is destined to go to hell, one may be able to atone for the sin by enduring a lesser form of suffering in this world. This is the case when one becomes ill as it is due to a past sin being atoned for in this world.”

Ōta Nyūdō-dono Gohenji, A Reply to Lay Priest Lord Ōta, Writings of Nichiren Shōnin, Volume 6, Followers I, Page 33