فَيَأْتِيَهُم بَغْتَةً وَهُمْ لَا يَشْعُرُونَ
Fayatiyahum baghtatan wahum l a yashAAuroon a that will come upon them [on resurrection,] all of a sudden, without their being aware [of its approach];
 - Mohammad Asad
which, in their heedlessness, will come to them suddenly.
 - Muhammad Farooq-i-Azam Malik
which will take them by surprise when they least expect 'it'.
 - Mustafa Khattab
So that it will come upon them suddenly, when they perceive not.
 - Marmaduke Pickthall
But the (Penalty) will come to them of a sudden while they perceive it not;
 - Abdullah Yusuf Ali