﴿ وَجَعَلْنَا مِنۢ بَيْنِ أَيْدِيهِمْ سَدًّۭا وَمِنْ خَلْفِهِمْ سَدًّۭا فَأَغْشَيْنَٰهُمْ فَهُمْ لَا يُبْصِرُونَ ﴾

“and We have set a barrier before them and a barrier behind them, and We have enshrouded them in veils so that they cannot see:”

And We have set before them a barrier read saddan or suddan in both instances and behind them a barrier; so We have covered them so they do not see — this is also figurative depicting the way in which the paths of faith are closed to them.