Likewise, ignorant patients often consume whatever they fancy. They refuse to keep to a regimen and cannot endure the bitter taste of medicine, because such restrictions delay the immediate comfort and pleasure they seek. Yet that momentary relief is followed by pains of far greater magnitude, or even by a hastened death. In exactly the same way, the children of Adam, through their ignorance and self-oppression, rush to obtain what their passions desire and abandon what their souls dislike, though it is what would set them right. The result is pain and punishment, in this world or the next, bringing severe torment and the greatest ruin.

Taqwa—that protective fear of Allah—is to shield oneself from what harms him by doing what benefits him. Shunning the harmful inevitably entails using the beneficial. If a person employs what benefits him while at the same time persisting in what harms him, he does not belong to the people of taqwa. As for abandoning both the harmful and the beneficial, that is impossible: when a servant can no longer take in nourishment, he lives off the reserves within his body, and those reserves eventually destroy him. For this reason the final outcome belongs to taqwa and to the muttaqun, because they guard themselves from what injures them; their end is submission to Allah and honor—even though, at the outset, they may feel the pain of taking the medicine and observing the regimen, just as the soul dislikes certain righteous deeds. The Exalted says: “Fighting has been prescribed for you, though it is hateful to you. It may be that you dislike something while it is good for you, and it may be that you love something while it is bad for you” (al-Baqarah 2:216). And because of the many alluring but futile deeds, He also says: “But whoever feared standing before his Lord and restrained his soul from desire, then Paradise will indeed be his refuge” (al-Naziʿat 79:40–41). Likewise, He said: “You were wishing that the unarmed party be yours” (al-Anfal 8:7).

Whoever refuses such protective measures will inevitably be harmed in the end. Someone who takes what benefits him, though mixed with a small amount of harm, is still in better condition than one who keeps a perfect regimen yet takes in almost nothing; for a total fast without nourishment itself causes illness. The same applies to the one who abandons sins yet performs no good deeds. Earlier we established a major principle: the category of good deeds is more beneficial than the mere avoidance of sins, just as nourishment is more beneficial than mere abstention. We also clarified that nourishment is sought for its own sake, whereas abstention is sought only when joined to something else.

Just as it is obligatory to keep away from the causes of physical illness before they appear and to remove them after they set in, so too with the diseases of the heart: one must preserve its health from the outset and restore it whenever sickness arises. Health is preserved by things of like nature and disease is removed by its opposite. Thus the heart’s health is maintained by employing what resembles what is already within it—whatever strengthens knowledge and faith, such as remembrance, reflection, and the prescribed acts of worship—and its sickness is removed by the contrary: doubts are driven away by clear proofs, and the love of falsehood is expelled by hating it and loving the truth.

For this reason Yahya ibn ʿAmmar said: “Knowledge is of five kinds. One kind is the life of the religion—and that is the knowledge of tawḥīd. Another kind is the food of the religion—and that is the knowledge that brings one to reflect on the meanings of the Quran.”