Is it God or Satan who appoints a companion [Qareen] to a person?

The Qareen (constant companion from among the jinn) is a trial from Allah for His servants. This is indicated by His Almighty's saying: "And We appointed for them companions (from among jinn), and they made attractive to them what was before them and what was behind them." (Quran 41:25) and His saying: "And whoever turns away from the remembrance of the Most Merciful - We will appoint for him a devil, so he will be to him a companion." (Quran 43:36) And in the Hadith: "There is no one among you but has had his Qareen from among the jinn appointed to him." The servant must protect himself from the Qareen's evil by striving against the doubts and desires it presents, repelling them with patience and certainty, and engaging in inviting people to guidance.