Overall meaning : Allah Almighty sheds light on the source of the Qur’an, the angel who brought it down, its recipient and the language in which it was revealed. He says: Truly, this Qur’an is divine revelation that has been sent down by the Lord of all the worlds. Gabriel, who has been entrusted with the task of conveying Allah’s revelation to His messengers, has brought it down upon your heart, Muhammad—so that you may warn people with it—in plain Arabic language.
Then He demonstrates the truthfulness of this Qur’an and that of the one who has brought it: This Qur’an is truly mentioned and foretold in the previously revealed divine books. Is it not sufficient proof of its truthfulness for these unbelieving idolaters that the learned among the Children of Israel recognize its truthfulness and find it written in their books?!
Next, He points out the Arab idolaters’ stubborn denial of the truth: Had We revealed this Qur’an to a non-Arab man who does not speak Arabic and he had recited it to your idolatrous people, Muhammad, in other than Arabic, they still would not have believed in it and they would have said, ‘We do not understand it!’ Thus have We caused the Qur’an to enter the hearts of the idolaters but they have rejected it, and they will not believe in it until they see Allah’s painful punishment, which will come upon them suddenly when they least expect it. They will say, upon seeing the punishment, ‘Can we have more time, our Lord, so we may repent, believe and do righteous deeds?!’
Do these unbelievers really wish that We hasten Our punishment? Consider this: If We do allow them to enjoy this life for many years, then Allah’s punishment with which they were threatened comes upon them, will their enjoyment in this world and the respite We give them be of any benefit to them at all?!
The Almighty then clarifies His immutable law that never fails: Never have We destroyed the wrongdoing people of a city of the past without sending them messengers to warn them of Our wrath and punishment if they persisted in their unbelief, and We were never unjust to them by inflicting punishment to them after having established proof against them and warned them enough.