al-Dukhān

رَبَّنَا اكْشِفْ عَنَّا الْعَذَابَ إِنَّا مُؤْمِنُونَ

أَنَّی لَهُمُ الذِّكْرَی وَقَدْ جَاءَهُمْ رَسُولٌ مُبِينٌ

12. [People will say]: “Our Lord! Remove the torment from us, really we shall believe!”
13. How can there be for them an admonition when a Messenger explaining things clearly has already come to them [though they ignored them].

Those who have taken religion as a mere play will notice their neglect and doubt one day. They will offer their supplications since Divine Wrath follows sending the last guidance and there will be no avail in repentance after being afflicted with torment. Consequently, the two blessed Verses say that when disbelievers notice the tokens of torment and the approach of the Resurrection Day, they will regret their past evil deeds and say that they believe but their repentance will be of no avail since the torment will approach them and what exists in them potentially will be actualized. When the Messenger and Divine Guidance (S) called them to believe in God, they turned away from him and lost the opportunity to act and save themselves.