Al-Kahf 18:91

<h2>His Journey East</h2><p>Allah tells us that Dhul-Qarnayn then traveled from the west of the earth towards the east. Every time he passed a nation, he subjugated the people and called them to Allah. If they obeyed him, all well and good, otherwise he would humiliate them and take their wealth and possessions. From every nation he took what his armies needed to fight the next nation. When he reached the place where the sun rises, as Allah says,</p><div class="arabic uthmani">وَجَدَهَا تَطْلُعُ عَلَى قَوْمٍ</div><p>(he found it rising on a people) meaning a nation,</p><div class="arabic uthmani">لَّمْ نَجْعَل لَّهُمْ مِّن دُونِهَا سِتْراً</div><p>(for whom We (Allah) had provided no shelter against the sun.) meaning, they had no buildings or trees to cover them and shade them from the heat of the sun. Qatadah said, "It was mentioned to us that they were in a land where nothing grew, so when the sun rose they would go into tunnels until it had passed its zenith, then they would come out to go about their daily lives and earn themselves a living."</p><div class="arabic uthmani">كَذَلِكَ وَقَدْ أَحَطْنَا بِمَا لَدَيْهِ خُبْراً </div><p>(So (it was)! And We knew all about him.) Mujahid and As-Suddi said, "This means that Allah …

So (it was). And We knew all concerning him.

(He left them) as they were: We completely understood what was before him.

So (it was)! And We knew all about him (Dhul-Qarnain).

And so it was. We had full knowledge of what he had.