مَّا يُقَالُ لَكَ إِلَّا مَا قَدْ قِيلَ لِلرُّسُلِ مِن قَبْلِكَ ۚ إِنَّ رَبَّكَ لَذُو مَغْفِرَةٍ وَذُو عِقَابٍ أَلِيمٍ Qur’an Fussilat (41:43)M a yuq a lu laka ill a m a qad qeela li l rrusuli min qablika inna rabbaka la th oo maghfiratin wa th oo AAiq a bin aleem in
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.