al-Anwār al-Ẓāhira (Manifest Lights)

The lights (nūr) that appear in the friends of God (awliyāʾ) are nothing other than the shining of the lights of prophethood (nubuwwa) upon them. The Muḥammadan Reality (ḥaqīqat-i Muḥammadiyya) is like the sun. The lights of the hearts (qulūb) of the awliyāʾ are like the moons. The illumination of the moon is due to the reflection of the sun's rays upon it, as it faces the sun. The sun itself illuminates the day, and at night, when its light is reflected upon the moon, its radiance appears on the moon, and thus, it never truly sets. From this example, you have understood that since the light of the Messenger of God (peace be upon him) is perpetual, it is necessary that the lights of the saints (awliyāʾ) are also perpetual. In their ḥāl (spiritual state), the saints (awliyāʾ) are the verses (āyāt) that Allah recites to His servants, manifesting them in various ways. (Nafahāt, 101)