Sura 21 Al-Anbiya (The Prophets), ayah 96

1. حَتَّىٰ إِذَا فُتِحَتْ يَأْجُوجُ وَمَأْجُوجُ وَهُمْ مِنْ كُلِّ حَدَبٍ يَنْسِلُونَ

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

   21:96

Translation: Saheeh International