anyone who invokes the divine decree to justify such conduct—all of this is firmly rooted in the innate dispositions and reason of all people, while the great majority of them (1) affirm the divine decree. Their condition could not remain sound, nor could they continue to exist in this world, if they allowed everyone to commit whatever corrupt deeds he wished and then invoke the divine decree as justification. We have already explained (2) that those who invoke the divine decree to justify sins, if they consistently applied their position, would be more unbelieving than the Jews and Christians; indeed, they are worse than those who deny the divine decree (3).

The third aspect:

When things universally acknowledged to be divinely decreed are harmful, it is proper to ward them off and, once they occur, remove them (4). Illness and the like, for example, are by common agreement brought about by Allah and willed by Him. Despite this, it is proper for a person to prevent them from occurring by taking precautions and avoiding their causes, and to strive to remove them after they occur. This (5) entails removing what Allah has willed.

If it were said that amputating a thief’s hand prevents what Allah wills, then taking medicine to cure an illness would likewise prevent (6) what Allah wills. The same would apply to warding off (7) a flood coming down a slope, a fire that is about to burn down houses, and setting upright a wall that is about to collapse, just as al-Khidr set that wall upright. The same applies to dispelling hunger by eating, dispelling the cold one feels (8) by warming oneself, and dispelling heat by seeking shade.