Overall meaning : The argument of those who argue with the believers about Allah’s religion, after people have embraced it, is futile and has no basis whatsoever with their Lord. Allah’s wrath has fallen upon them in this life, and they will suffer a harsh punishment in the life to come.
It is Allah who has sent down the Qur’an to His Messenger with the truth and has sent down justice so that people may conduct themselves with fairness. You just do not know, Muhammad! The time of Judgement Day may well be near and fast approaching. Those who do not believe in it mockingly ask for its coming to be hastened, but those who believe in it dread its coming and know it to be the truth. Indeed, those who doubt the Day of Judgement have strayed far away from the truth.