Allah is the Light of the heavens and the earth; the parable of His Light is like a niche in which there is a lamp, the lamp is into the glass, the glass is as if a brilliant star lit from a blessed olive tree, neither of the East nor the West, whose oil would almost glow even if untouched with fire; Light upon light. Allah guides to His Light whom He wishes, and Allah presents a parable for mankind, and Allah is the Knower of everything.
Lord is introduced as the Light of the universe. Darkness is compared to Satan. In verse, the fuel of the lamp is an olive tree that is not from the east or the west, so the oil will be without any water content since it is exposed always to the sunlight. There will be no smoke for such a lamp.
Adhikr is told as the Light in verse 4: 174. So whoever holdfasts Adhikr, he did holdfast Lord and is guided into the Straightpath as explained in verse 5: 48. But the Arabic Quran reading Fujjar by hiding and rejecting Adhikr are wandering into the darkness as explained in verse 2: 257. See explanation 7: 157-158 and 14: 1-2.