18:95
قَالَ مَا مَكَّنِّى فِيهِ رَبِّى خَيْرٌۭ فَأَعِينُونِى بِقُوَّةٍ أَجْعَلْ بَيْنَكُمْ وَبَيْنَهُمْ رَدْمًا
He said, "That in which my Lord has established me is better [than what you offer], but assist me with strength; I will make between you and them a dam.
Translation · Saheeh International
Tafsir
Ibn Kathīr (abridged)
His Journey to the Land of Ya'juj and Ma'juj, and building the Barrier
Allah says of Dhul-Qarnayn:
ثُمَّ أَتْبَعَ سَبَباً
(Then he followed (another) way) meaning, he traveled from the east of the earth until he reached a place between the two mountains which were next to one another with a valley in between, from which Ya'juj and Ma'juj (God and Magog) will emerge into the land of the Turks and spread mischief there, destroying crops and people. Ya'juj and Ma'juj are among the progeny of Adam, peace be upon him, as was recorded in the Two Sahihs;
«إِنَّ اللهَ تَعَالَى يَقُولُ: يَا آدَمُ فَيَقُولُ: لَبَّيْكَ وَسَعْدَيْكَ فَيَقُولُ: ابْعَثْ بَعْثَ النَّارِ، فَيَقُولُ: وَمَا بَعْثُ النَّارِ؟ فَيَقُولُ: مِنْ كُلِّ أَلْفٍ تِسْعُمِائَةٍ وَتِسْعَةٌ وَتِسْعُونَ إِلَى النَّارِ وَوَاحِدٌ إِلَى الْجَنَّةِ، فَحِينَئِذٍ يَشِيبُ الصَّغِيرُ وَتَضَعُ كُلُّ ذَاتِ حَمْلٍ حَمْلَهَا. فَقَالَ: إِنَّ فِيكُمْ أُمَّتيْنِ مَا كَانَتَا فِي شَيْءٍ إِلَّا كَثَّرَتَاهُ يَأْجُوجَ وَمَأْجُوج»
"Allah said: "O Adam." Adam said, "Here I am at Your service." Allah said, "Send forth the group of Hellfire." Adam said, "What is the group of Hellfire" Allah said: "Out of every thousand, nine hundred and ninety-nine will go to Hell and one will go to Paradise." At that time young men will turn grey and every pregnant female will drop her load. Among you are two nations who never come to anything but they overwhelm it with their huge numbers. (They are) Ya'juj and Ma'juj."