Surah Al-Anbiya, ayah 96

21:96

حَتَّىٰٓ إِذَا فُتِحَتۡ يَأۡجُوجُ وَمَأۡجُوجُ وَهُم مِّن كُلِّ حَدَبٖ يَنسِلُونَ ٩٦

Hattā idhā futihat ya'jūju wama'jūju wahum min kulli hadabin yansilūn

Until when [the dam of] Gog and Magog has been opened and they, from every elevation, descend