﴿ 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 a bar) a veil (before them) of the matter of the Hereafter (and a bar) a veil (behind them) of the matter of this worldly life, (and (thus) have covered them) covered the insight of their hearts (so that they see not) the Truth and guidance; it is also said that this means: We have set a veil before them when they were about to stone the Prophet (pbuh) while he was praying, such that they did not see him; and We set behind them a veil so that they do not see the Companions of the Prophet (pbuh); and because of this veil they were not able to see the Prophet (pbuh) or consequently harm him.