Pure evil doesn’t exist

Evil, as an independent phenomenon whereby no dimension of good is involved, has no existence in this world. There is nothing in our existence that can be called pure evil, because every evil in this world is good from one angle or another. For instance, sickness harms the body from one angle, while from other angles tests patience, evokes resilience, and may even strengthen immunity. Most disliked things are usually this way; never void of some benefit or another for the human being.

Ibn al-Qayyim, Shifā’ al-‘Alīl fī Masā’il al-Qaḍā’i wal-Qadari wal-Ḥikmati wat-Ta‘līl (Cairo: Dar at-Turath, 1978), pp. 380-413. Referenced in Yaqeen Institute website.