Until when [the dam of] Gog and Magog has been opened and they, from every elevation, descend
The Saheeh International Quran Translation
حَتَّىٰٓ إِذَا فُتِحَتْ يَأْجُوجُ وَمَأْجُوجُ وَهُم مِّن كُلِّ حَدَبٍ يَنسِلُونَUntil when [the dam of] Gog and Magog has been opened and they, from every elevation, descend