al-Mu sib (‘he who examines his conscience’), Ab ‘Abd All h rith
( c. 781–857 (AH 165–243)). Sh fi‘ite theologian who turned to ascetic renunciation and moral purification, and is regarded as the first Sunni mystic ( S f ) to organize a theologically systematic approach to God. He was a prolific writer, with about 200 works ascribed to him. His Kit b al-ri‘ ya li- uq q Allah (The Book of Observance of that which is Owed to God) is a book of spiritual advice, which includes the importance of self-examination (Arab., mu saba ), hence his name.