Can jinn be given power over a believer, and what should a committed sister do if she thinks that a jinn is afflicting her, especially since her uncommitted sister was possessed by a jinn and it did not depart with the Qur’an?

We hope that God protects the believer who maintains the prescribed remembrances (adhkar) and protective supplications (ta'awwudhat) from the domination of jinn, based on the Prophet's (peace be upon him) saying: "Say 'Qul Huwa Allahu Ahad' (Surah Al-Ikhlas) and the two 'Mu'awwidhatayn' (Surahs Al-Falaq and An-Nas) three times in the evening and in the morning; they will suffice you against everything." Ruqyah Shar'iyyah (Islamic incantation) is a beneficial treatment, though its benefit may be delayed or its effect weakened due to the religious weakness of the reciter (raqi) or the one upon whom it is recited (marqi). Therefore, it is necessary to seek a raqi who is upright in his religion, and for the marqi to avoid sins and cleanse the place of anything displeasing to God.