Surah Al-Anbya — Ayah 96 (21:96)
حَتَّىٰٓ إِذَا فُتِحَتۡ يَأۡجُوجُ وَمَأۡجُوجُ وَهُم مِّن كُلِّ حَدَبٖ يَنسِلُونَ ٩٦
English translation (Saheeh International)
Until when [the dam of] Gog and Magog has been opened and they, from every elevation, descend
Brief commentary
They will never return, even until the barrier of Gog and Magog is opened and they begin emerging, hurriedly descending from every high piece of land.