One of the two key principles of the Muעtazila was the emphasis on the omnibenevolence and justice of God (עadl). Among the issues that this raised was that of the origin of evil. That is, where does pain and suffering come from? For the Muעtazila, the principle of עadl demands that humans have freedom of choice and so have the ability to create evil, pain, and suffering. However, there is suffering, such as that caused by nature or illness, that is not the responsibility of humans and must be created by God. For this reason, even this suffering, although it appears bad, must be good because it comes from God. Heemskerk explores how עAbd al-Jabbar (d. 1024), a very important Muעtazili theologian, developed this theodicy by arguing that pain is divine assistance and that either here or in the hereafter the afflicted person will be compensated.