Surah Al-Kahf, ayah 94

18:94

قَالُواْ يَٰذَا ٱلۡقَرۡنَيۡنِ إِنَّ يَأۡجُوجَ وَمَأۡجُوجَ مُفۡسِدُونَ فِي ٱلۡأَرۡضِ فَهَلۡ نَجۡعَلُ لَكَ خَرۡجًا عَلَىٰٓ أَن تَجۡعَلَ بَيۡنَنَا وَبَيۡنَهُمۡ سَدّٗا ٩٤

Qālū yādhal-qarnayni inna ya'jūja wama'jūja mufsidūna fil-ardi fahal naj'alu laka kharjan 'alā an taj'ala baynanā wabaynahum saddā

They said, "O Dhul-Qarnayn, indeed Gog and Magog798 are [great] corrupters in the land. So may we assign for you an expenditure that you might make between us and them a barrier?"

Footnotes

798 Savage tribes who had ravaged large parts of central Asia, committing every kind of atrocity.