سُبْحَانَ ٱللَّٰهِ
Holy Qur'an
Al-Qur'an
Kids Qur'an
This is an allusion to the allegation of the Prophet's opponents that he himself was the "author" of what he claimed to be a divine revelation, as well as to their demand that he should "prove" the truth of his prophetic mission by producing a miracle: a scornful attitude with which all the earlier prophets had been confronted at one time or another, and which is epitomized in the "saying" of the unbelievers mentioned in verse {5} of this surah.
The gist of Allah's Message, now, before, and for ever, is the same: Mercy to the erring and repentant; just punishment to those who wilfully rebel against Allah.