بَلْ تَأْتِيهِم بَغْتَةًNay, it will come upon them all of a sudden,means, the Fire will come upon them suddenly, i.e., it will take them by surprise. فَتَبْهَتُهُمْand will perplex them,means, it will scare them, and they will succumb to it in confusion, not knowing what they are doing. فَلَ يَسْتَطِيعُونَ رَدَّهَاand they will have no power to avert it,means, they will have no means of doing so. وَلَا هُمْ يُنظَرُونَnor will they get respite.means, it will not be delayed for them even for an instant.