Sura al-Imral [Medina]

The Quranic text and Ali’s version

يَوْمَ تَبْيَضُّ وُجُوهٌ وَتَسْوَدُّ وُجُوهٌ...

3:106. On the day when some faces will be (lit up with) white, and some faces will be (in the gloom of) black;

C432. The "face" (wajh) expresses our Personality, our inmost being.

White is the colour of Light; to become white is to be illumined with Light, which stands for felicity, the rays of the glorious light of Allah.

Black is the colour of darkness, sin, rebellion, misery; removal from the grace and light of Allah.

These are the Signs of heaven and hell. The standard of decision in all questions is the justice of Allah.

...فَأَمَّا الَّذِينَ اسْوَدَّتْ وُجُوهُهُمْ أَكْفَرْتُم بَعْدَ إِيمَانِكُمْ...

to those whose faces will be black, (will be said):

"Did ye reject faith after accepting it?

...فَذُوقُواْ الْعَذَابَ بِمَا كُنْتُمْ تَكْفُرُونَ ﴿١٠٦﴾

Taste then the penalty for rejecting faith.