So the vestiges are His manifestations—exalted is He—wherein the gnostics witness Him, while they are simultaneously the veils hiding Him—exalted is He—from those who are veiled. Just as when a mirror stands opposite another mirror, the contents of each mirror appear within the other; similarly, it is said in divine knowledge: the created being is the mirror of the Creator—exalted is He—in which He sees His Names, or say, He sees His Essence individuated by some of His Names.

Some of them said: The Truth is a perpetual light, while the shadow stems from deviation, darkness resides within the shadow, and peril resides within the darkness. Therefore, uprightness (al-istiqamah) has no shadow, no darkness issues from it, and no peril accompanies it. The existence of darkness within the soul stems from the shadow of the dense self; so whoever extracts his self from his soul becomes filled with a brilliant light, and darkness vanishes from him. The men of Allah stand between two lights: the light of faith before them, and the light of righteous actions behind them.

And from the book The Admonition (Al-Tanbih) by Hasan b. Khamriyy: Truthfulness (al-sidq) is the spirit of faith, faith is the spirit of actions, and actions are the form of Allah.