An-Nur
Allah is An-Noor, The One who illuminates and reveals the divine light of all the worlds. His light illuminates the heart and provides clarity and guidance. Anyone who turns their back to the true light will be left in the darkness.
From the root n-w-r which has the following classical Arabic connotations: to give light, to illuminate, to fill with light to clarify, to reveal, to make visible to blossom, to be in bloom (revealed) to be flaming, blazing and apparent to the senses to enlighten, give counsel, and give advice.
So, believe in Allah and His Messenger and the Light which We have sent down. And Allah, of what you do, (is) All-Aware. (Quran 64:8)
Allah is the Light of the heavens and the earth. The example of His light is like a niche within which is a lamp, the lamp is within glass, the glass as if it were a pearly [white] star lit from [the oil of] a blessed olive tree, neither of the east nor of the west, whose oil would almost glow even if untouched by fire. Light upon light. Allah guides to His light whom He wills. And Allah presents examples for the people, and Allah is Knowing of all things. (Quran 24:35)