 He wrote extensively on mysticism, arguing it to be the only right path to truth. A notable piece among his writings on mysticism is The Niche of Light (Mishkāt al-anwār), a significant work of an illuminationist nature and one that influenced the formation of the doctrine of illumination (ishrāq) by Suhrawardī (Aminrazavi 1996). Also, parts of his Magnum Opus, Revival of Religious Sciences (Iḥyā’ al-‘ulūm al-dīnī), such as book thirty-five of the Iḥyā’: The Book of Faith in Divine Unity and Trust in Divine Providence, are essentially devoted to an explication of the Sufi doctrine. He also has written numerous shorter commentaries on the spiritual significance of fasting, praying, invocation of divine names and attributes, and spiritual music as instruments of the catharsis of the soul.