﴿ حَتَّىٰٓ إِذَا فُتِحَتْ يَأْجُوجُ وَمَأْجُوجُ وَهُم مِّن كُلِّ حَدَبٍۢ يَنسِلُونَ ﴾

“until such a time as Gog and Magog are let loose [upon the world] and swarm down from every corner [of the earth],”

Until hattā a particle expressing the end of the prohibition of their return when Gog and Magog read Ya’jūju wa-Ma’jūju or Yājūju wa-Mājūju these are non-Arabic names of two tribes; there is an implicit genitive annexation before this clause namely the gates of the sadd ‘the barrier’ built against them are let loose read futihat or futtihat — and this will happen near the time of the Resurrection — and they slide down they hasten from every slope every highland.