Surah 6. Al-An'am, Ayah 1

Both "darkness" and "light" are used here in their spiritual connotation. As always in the Qur'an, "darkness" is spoken of in the plural (zulumat) in order to stress its intensity, and is best translated as "deep darkness" or "depths of darkness".

 “Light” is always used in the Quran in the singular (nûr), whereas “darkness” is used in the plural (ẓulumât). Nûr is usually used in a metaphorical sense to refer to true guidance, whereas ẓulumât refers to different forms of misguidance.

Adala has various meanings: (1) to hold something as equal to something else, as here; to balance nicely; (2) to deal justly, as between one party and another, xiii.15; (3) to give compensation or reparation, or something as equivalent to something else, vi. 70; (4) to turn the balance the right way, to give a right disposition, to give a just bias or proportion, lxxxii. 7; (5) to turn the balance the wrong way, to swerve, to show bias. iv 135.

The argument is threefold: (1) God created everything you see and know: how can you then set up any of His own creatures as equal to Him? (2) He is your own Guardian-Lord; He cherishes and loves you: how can you be so ungrateful as to run after something else? (3) Darkness and Light are to help you to distinguish between the true from the false: how then can you confound the true God with your false ideas and superstitions? There may also be a repudiation of the Duality of old Persian theology; Light and Darkness are not conflicting Powers; they are both creatures of the one true God.