Surah Al-Kahf (18) — Ayah 91

(Ayah 91) ➊ {كَذٰلِكَ وَ قَدْ اَحَطْنَا … :} That is, his treatment with the people of the East was also like that with the people of the West, or it means that no one should consider it impossible for him to traverse all the regions between the East and the West. Indeed, this is what happened, and the armies and equipment he arranged for this purpose, and the way he abandoned his comforts and endured the hardships of continuous journeys and battles, We alone have full knowledge of it—who else knows?
➋ The first lesson to be learned from the life of Dhul-Qarnayn is that as soon as they gain power, high-spirited Muslim rulers, even in their youth, resolve to conquer the whole world, because Dhul-Qarnayn, with such immense armies, needed a long period for such lengthy and difficult journeys and the battles that came his way. The second lesson is that although there is pleasure and enjoyment in living among royal palaces, peacocks and music, carpets and brocades, surrounded by beauties and courtiers, yet the exhilaration found in riding on horseback, crossing mountains, deserts, forests, and rivers, fighting jihad with enemies, getting wounded, and then tasting victory and raising the banner of Islam, cannot be compared to the pleasure of luxury.
➌ After gaining power, the mission of our Noble Prophet (peace and blessings be upon him) and his caliphs was also to spread Islam from East to West through continuous jihad, and the Prophet (peace and blessings be upon him) was commanded to fight all the people of the world until they accepted Islam or, by paying jizyah, became subdued and subjugated. Allah Almighty showed him all the Easts and Wests of the earth and informed him that the dominion of his Ummah would reach there. [ ابن ماجہ، الفتن، باب ما یکون من الفتن : ۳۹۵۲ ] And in fact, within a few years, Qutaybah bin Muslim (may Allah have mercy on him) had reached the farthest East, and Uqbah bin Nafi‘ (may Allah have mercy on him) had reached the farthest West. As for the regions left to the South and North, the Prophet (peace and blessings be upon him) also said: [ لاَ يَبْقٰی عَلٰی ظَهْرِ الْأَرْضِ بَيْتُ مَدَرٍ وَلَا وَبَرٍ إِلَّا أَدْخَلَهُ اللّٰهُ كَلِمَةَ الْإِسْلَامِ بِعِزِّ عَزِيْزٍ أَوْ ذُلِّ ذَلِيْلٍ إِمَّا يُعِزُّهُمُ اللّٰهُ عَزَّوَجَلَّ فَيَجْعَلُهُمْ مِنْ أَهْلِهَا أَوْ يُذِلُّهُمْ فَيَدِيْنُوْنَ لَهَا ] [ مسند أحمد : 4/6، ح : ۲۳۸۷۶، عن المقداد و عائشۃ علیھا السلام ] “There will not remain a house (or tent) made of bricks or hair on the face of the earth except that Allah will cause the word of Islam to enter it, honoring the honorable and humiliating the humiliated—either He will honor them and include them among those who recite this word, or He will humiliate them and they will become subjugated to it.” Now, let us see when that Muhammadan Dhul-Qarnayn will arise who will accomplish this feat? In any case, instead of waiting for some Dhul-Qarnayn, it is incumbent upon all of us to remain constantly engaged in jihad as much as possible, to provide the necessities for raising the banner of Islam and eradicating disbelief, and to subdue the enemies—who knows whom Allah will grant this honor! This was the mission and action of Dhul-Qarnayn, this was the mission and action of our beloved Prophet and his caliphs, and this is the task assigned to us.
➍ As mentioned in the commentary at the beginning of the surah, memorizing the initial or final verses of this surah protects from the tribulation of Dajjal, about whom the Messenger of Allah (peace and blessings be upon him) said: [ مَا بَيْنَ خَلْقِ آدَمَ اِلٰی قِيَامِ السَّاعَةِ خَلْقٌ أَكْبَرُ مِنَ الدَّجَّالِ ] [ مسلم، الفتن، باب في بقیۃ من أحادیث الدجال : ۲۹۴۶، عن عمران بن حصین رضی اللہ عنہ ] “From the creation of Adam (peace be upon him) until the establishment of the Hour, there has not been any creature greater than Dajjal.” Then whoever is protected from him will, all the more so, be protected from other tribulations. The summary of the stories of the Companions of the Cave and Dhul-Qarnayn is that a believer cannot coexist with the disbelievers who cause tribulation. If he does not have power, he goes to caves and mountains to save his faith, and Allah protects both his life and faith. And if he is in power, he spends his entire life breaking the back of disbelief and the disbelievers, so that they do not become dominant and pose a threat to his faith. It is also understood that merely reciting this surah or some of its verses is not sufficient; rather, acting upon its requirements is also necessary to be saved from tribulations. It is not that one befriends others besides Allah, lulls his zeal for one's faith to sleep, remains silent on disbelief and polytheism, lives a life of luxury in a disbelieving society, and merely recites Surah al-Kahf every Friday; rather, acting upon the memorized verses is also included. For details, see Surah al-Kahf (102–104).

91. 1 That is, what We have stated about Dhul-Qarnayn is exactly as We have described: first he reached the farthest west and then the farthest east, and We have complete knowledge of all his abilities, means and resources, and all other matters concerning him.

91. So it was. And We had full knowledge of all that befell Dhul-Qarnayn [75].

[75]
The Second Expedition of Dhul-Qarnayn Towards the East:

One meaning of the word ﴿كذٰلك﴾ is that, regardless of what others or historians may say about the circumstances of Dhul-Qarnayn, the real event is what We are narrating, and We know well what situations Dhul-Qarnayn faced and what he possessed. The second meaning of ﴿كذٰلك﴾ is that Dhul-Qarnayn treated this nation in the same way as he had treated the western nation, that is, he taught and invited them to Islam; those who acted rebelliously were dealt with strictly, and those who chose the path of obedience were treated with kindness.