﴿ حَتَّىٰٓ إِذَا بَلَغَ مَغْرِبَ ٱلشَّمْسِ وَجَدَهَا تَغْرُبُ فِى عَيْنٍ حَمِئَةٍۢ وَوَجَدَ عِندَهَا قَوْمًۭا ۗ قُلْنَا يَٰذَا ٱلْقَرْنَيْنِ إِمَّآ أَن تُعَذِّبَ وَإِمَّآ أَن تَتَّخِذَ فِيهِمْ حُسْنًۭا ﴾

“[And he marched westwards] till, when he came to the setting of the sun, it appeared to him that it was setting in a dark, turbid sea; and nearby he found a people [given to every kind of wrongdoing]. We said: "O thou Two-Horned One! Thou mayest either cause [them] to suffer or treat them with kindness!"”

(Till, when he reached the setting place of the sun) where the sun sets, (he found it setting in a muddy spring) a blackened, muddy and stinking spring; it is also said that this means: a hot spring, (and found a people thereabout) these people were disbelievers: (We said: O Dhu'l-Qarnayn!) We inspired him (Either punish) either kill them until they accept to believe that there is no deity except Allah (or show them kindness) or you pardon them and let them be.