18:97

Al-Kahf 18:97

فَمَا ٱسْطَٰعُوٓا۟ أَن يَظْهَرُوهُ وَمَا ٱسْتَطَٰعُوا۟ لَهُۥ نَقْبًۭا

Famas taa'ooo any yazharoohu wa mastataa'oo lahoo naqbaa

So they were not able to scale it nor could they make a hole in it.