فَمَا ٱسْطَـٰعُوٓا أَن يَظْهَرُوهُ وَمَا ٱسْتَطَـٰعُوا لَهُۥ نَقْبًا

Fama istaAAoo an yathharoohuwama istataAAoo lahu naqba

So they [i.e., Gog and Magog] were unable to pass over it, nor were they able [to effect] in it any penetration.