God tells us that suffering or illness comes from our minds in song 10 of the Mikagura-uta. Most people when they are ill, or when their children are ill, will vehemently argue with you when you tell them that illness comes from their minds. They will tell you that God does not punish. But my question to them is, if illness does not come from the mind, who or what brings it upon them. If they believe in God, why is God letting this happen? What is the purpose of suffering or illness? Is it random, and is its cure also random? I know there are people that would say they were cured because of their belief in God, but what about the many others that died despite their belief in a higher being? Does God favor one person over the other?
There are many people who do believe that God will favor them because they believe in a particular teaching, and God will also punish those that do not believe in their religion. In the Osashizu there is a passage that says that there is suffering and joy in the world; and there is also evil and good in the world. We are seeing both cause (what people are doing now) and effect (fate appearing from past actions) in the world today, but most people cannot see this because the effect of our actions are often delayed. We reap what we have sowed. God for the most part is a spectator watching the world with hope.
But if illness or suffering comes from the mind, by what mechanism does this work? God in the first verse of the most sacred scripture (Ofudesaki), tells us we do not understand the heart or mune. It is the heart we must first understand. God tells us that it is our own hearts that monitors our behaviors. It is not God, or any evil forces that brings upon suffering. We control our own fates. We only need to eliminate the dusts or evil thoughts of regret (oshii), covetousness (hoshii), self-love (kawaii), greed (yoku), and arrogance (komam). It is our own hearts that remind us of these dusts in our minds, by delivering these fates that were caused by acting on these same evil thoughts. This is why God tells us that illness and suffering comes from our own minds! God also tells us to ponder what fate comes from our hearts. God wants us not to blame others, but calm our own minds, and ponder the dusts in our own minds, and not act upon them. This is how we purify our minds, so our hearts will bring upon only positive fate.
In summary, we are not telling you that you are evil and bad because you or your children are suffering or have illness. But we are telling you that these symptoms or appearances are messages from your own heart that there are dusts in your minds. It is these same dusts that created the sufferings and illness that you may be experiencing now. By not taking action upon these dusts, one can purify one’s own minds so only joy comes from the heart.
*in our teachings, we are told that our own children may suffer from our own fates until they are 13 years of age. After that, any illness or suffering comes from their own fates.
Heaven's Truths, in Healing the Body 