حَتَّىٰٓ إِذَا بَلَغَ مَغۡرِبَ ٱلشَّمۡسِ وَجَدَهَا تَغۡرُبُ فِي عَيۡنٍ حَمِئَةٖ وَوَجَدَ عِندَهَا قَوۡمٗاۖ قُلۡنَا يَٰذَا ٱلۡقَرۡنَيۡنِ إِمَّآ أَن تُعَذِّبَ وَإِمَّآ أَن تَتَّخِذَ فِيهِمۡ حُسۡنٗا

Hattaaa izaa balagha maghribash shamsi wajadahaaa taghrubu fee 'aynin hami'a tinw wa wajada 'indahaa qawmaa; qulnaa yaa Zal Qarnaini immaaa an tu'az ziba wa immaaa an tattakhiza feehim husnaa

Until, when he reached the setting of the sun, he found it set in a spring of murky water: Near it he found a People: We said: "O Zul-qarnain! (thou hast authority,) either to punish them, or to treat them with kindness."

— Al-Kahf (ٱلْكَهْف), 18:86