so great, so too the difference between the heart’s sight—its perception of realities—and the sight of the eyes is such that only Allah can measure it. The purpose here is simply to draw a comparison between the two kinds of illness. Treating spiritual ailments thus follows the same pattern as treating bodily ailments. Sulaymān wrote to Abū al-Dardā’:

“To proceed: I have heard that you have set yourself up as a physician. Beware, then, lest you kill.”

Allah sent down His Book as a healing for what is in the hearts. He, Most High, says:

“We send down of the Quran that which is a healing and a mercy to the believers, but it increases the wrongdoers in nothing but loss.”

This is because healing comes only to those who deliberately take the remedy: the believers, who apply the remedy of the Quran to the ailments of their hearts.

Bodily illness occurs when natural appetite and aversion depart from balance: through craving what cannot be obtained, or losing beneficial appetite, recoiling from what is wholesome, and losing aversion to what is harmful. It also occurs through weakness in the powers of perception and movement. Likewise, illness of the heart arises through love and hatred that depart from balance. These are the desires of which Allah says:

“And who is more astray than one who follows his own desire without guidance from Allah?”

He also says:

“Rather, those who do wrong follow their own desires without knowledge.”

Similarly, the body departs from balance when a person indulges its cravings without following the physician’s advice. Illness also arises from weakness in the heart’s perception and power, leaving it unable to know and desire what benefits it and is good for it. And just as ignorant patients may consume whatever they crave and fail to