﴿ إِنَّ عَذَابَ رَبِّهِمْ غَيْرُ مَأْمُونٍۢ ﴾

“for, behold, of their Sustainer's chastisement none may ever feel [wholly] secure;”

Lo! the doom of their Lord is that before which none can feel secure) no guarantee of security has come to them from their Lord.