﴿ فَهَلْ يَنظُرُونَ إِلَّا ٱلسَّاعَةَ أَن تَأْتِيَهُم بَغْتَةًۭ ۖ فَقَدْ جَآءَ أَشْرَاطُهَا ۚ فَأَنَّىٰ لَهُمْ إِذَا جَآءَتْهُمْ ذِكْرَىٰهُمْ ﴾

“Are, then, they [whose hearts are sealed] wait­ing for the Last Hour - [waiting] that it come upon them of a sudden? But it has already been foretold! And what will their remembrance [of their past sins] avail them, once it has come upon them?”

(Await they aught) do the disbelievers of Mecca, if they disbelieve in you, await anything (save the Hour, that it should come upon them unawares) by surprise? (And the beginnings thereof) the signs of the coming of the Hour: the splitting of the moon and the coming of the Prophet (pbuh) with the Qur'an which are of its signs (have already come. But how, when it hath come upon them) i.e. the Hour, (can they take their warning) by repenting?