Surah Al Kahf Tafseer

حَتَّى إِذَا بَلَغَ مَغْرِبَ الشَّمْسِ

Until, when he reached the setting place of the sun,

means, he followed a route until he reached the furthest point that could be reached in the direction of the sun's setting, which is the west of the earth.

As for the idea of his reaching the place in the sky where the sun sets, this is something impossible, and the tales told by storytellers that he traveled so far to the west that the sun set behind him are not true at all. Most of these stories come from the myths of the People of the Book and the fabrications and lies of their heretics.

وَجَدَهَا تَغْرُبُ فِي عَيْنٍ حَمِيَةٍ

he found it setting in a spring of Hami'ah,

meaning, he saw the sun as if it were setting in the ocean. This is something which everyone who goes to the coast can see:it looks as if the sun is setting into the sea but in fact it never leaves its path in which it is fixed.

Hami'ah is, according to one of the two views, derived from the word Hama'ah, which means mud.

This is like the Ayah:

إِنِّى خَـلِقٌ بَشَرًا مِّن صَلْصَـلٍ مِّنْ حَمَإٍ مَّسْنُونٍ

"I am going to create a man (Adam) from dried clay of altered Hama'h (mud). (15:28),

which means smooth mud, as we have discussed above.

وَوَجَدَ عِندَهَا قَوْمًا

And he found near it a people.

meaning a nation.

They mentioned that they were a great nation from among the sons of Adam.

قُلْنَا يَا ذَا الْقَرْنَيْنِ إِمَّا أَن تُعَذِّبَ وَإِمَّا أَن تَتَّخِذَ فِيهِمْ حُسْنًا

We (Allah) said (by inspiration):"O Dhul-Qarnayn! Either you punish them or treat them with kindness."

means, Allah gave him power over them and gave him the choice:if he wanted to, he could kill the men and take the women and children captive, or if he wanted to, he could set them free, with or without a ransom. His justice and faith became apparent in the ruling he pronounced