Overall meaning : The unbelievers are not at all certain about the truth of what We have informed them. Rather, they are in doubt about it, amusing themselves and preoccupied with idle pursuits. Wait, then, Muhammad, for the day when the sky brings forth smoke for all to see. As it envelops people, they will cry out, ‘This is a painful torment. Lord, relieve us from this torment; we will be true believers if You do.’ But how can an admonition be of any benefit to these unbelievers after the punishment descends upon them, and when the messenger making the truth clear to them has already come to them, yet they disdainfully turn away from him, saying, ‘He is a taught the Qur’an by others; he is a madman’?!
We will remove that torment for a short while, but you are bound to return to your misguided ways. On the day We seize them violently and mightily, We will surely exact retribution from them.