Surah Al-Kahf, verse 85

وَيَسْـَٔلُونَكَ عَن ذِى ٱلْقَرْنَيْنِ ۖ قُلْ سَأَتْلُوا۟ عَلَيْكُم مِّنْهُ ذِكْرًا ﴿٨٣﴾

And they ask you, [O Muḥammad], about Dhul-Qarnayn. Say, "I will recite to you about him a report."

إِنَّا مَكَّنَّا لَهُۥ فِى ٱلْأَرْضِ وَءَاتَيْنَـٰهُ مِن كُلِّ شَىْءٍۢ سَبَبًۭا ﴿٨٤﴾

Indeed, We established him upon the earth, and We gave him from everything a way [i.e., means].

حَتَّىٰٓ إِذَا بَلَغَ مَغْرِبَ ٱلشَّمْسِ وَجَدَهَا تَغْرُبُ فِى عَيْنٍ حَمِئَةٍۢ وَوَجَدَ عِندَهَا قَوْمًۭا ۗ قُلْنَا يَـٰذَا ٱلْقَرْنَيْنِ إِمَّآ أَن تُعَذِّبَ وَإِمَّآ أَن تَتَّخِذَ فِيهِمْ حُسْنًۭا ﴿٨٦﴾

Until, when he reached the setting of the sun [i.e., the west], he found it [as if] setting in a body of dark water, and he found near it a people. We [i.e., Allāh] said, "O Dhul-Qarnayn, either you punish [them] or else adopt among them [a way of] goodness."

قَالَ أَمَّا مَن ظَلَمَ فَسَوْفَ نُعَذِّبُهُۥ ثُمَّ يُرَدُّ إِلَىٰ رَبِّهِۦ فَيُعَذِّبُهُۥ عَذَابًۭا نُّكْرًۭا ﴿٨٧﴾

He said, "As for one who wrongs, we will punish him. Then he will be returned to his Lord, and He will punish him with a terrible punishment [i.e., Hellfire].