Light of faith/iman and darkness of disbelief/kufr

God is the light of the heavens and the earth. The semblance of His light is that of a niche in which is a lamp, the flame within a glass, the glass a glittering star as it were, lit with the oil of a blessed tree, the olive, neither of the East nor of the West, whose oil appears to light up even though fire touches it not, -- light upon light. God guides to His light whom He will. So does God advance precepts of wisdom for men, for God has knowledge of everything.

(The light is lit) in houses of worship which God has allowed to be raised, and His name remembered in them. His praises are sung there morning and evening,

By men not distracted from the remembrance of God either by trade and commerce or buying and selling, who stand by their devotional obligations and pay the zakat, who fear the day when hearts and eyes would flutter with trepidation

That God may reward them for the best of their deeds, and bestow more on them of His bounty, for God gives whom He please without measure.

As for those who disbelieve, their deeds are like a mirage in the desert which the thirsty takes for water till he reaches it to find that there was nothing, and finds God with him who settles his account, for God is swift at the reckoning.

Or like darkness in a wide, wide sea, waves surging upon waves, with clouds overhanging, darkness on darkness. If you stretch your hand, you could hardly see it. For him whom God does not give any light, there is no light.