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Surah 46. Al-Ahqaf
Ayah 11 - 12
11 وَقَالَ ٱلَّذِينَ كَفَرُوا۟ لِلَّذِينَ ءَامَنُوا۟ لَوْ كَانَ خَيْرًا مَّا سَبَقُونَآ إِلَيْهِ ۚ وَإِذْ لَمْ يَهْتَدُوا۟ بِهِۦ فَسَيَقُولُونَ هَـٰذَآ إِفْكٌ قَدِيمٌ
12 وَمِن قَبْلِهِۦ كِتَـٰبُ مُوسَىٰٓ إِمَامًا وَرَحْمَةً ۚ وَهَـٰذَا كِتَـٰبٌ مُّصَدِّقٌ لِّسَانًا عَرَبِيًّا لِّيُنذِرَ ٱلَّذِينَ ظَلَمُوا۟ وَبُشْرَىٰ لِلْمُحْسِنِينَ
[11-12] Those who have refused to believe say with regard to those who have believed, "If it had been any good to believe in this Book, they would not have believed in it before us."15 As they have not received any guidance from it, they will surely say, "This is an ancient falsehood."16 Yet before it there has come the Book of Moses as a guide and a mercy, and this Book has been revealed to confirm it in the Arabic tongue so as to warn the wrongdoers17 and to give good news to those who have adopted the righteous conduct.
15This is one of those arguments that the chiefs of the Quraish employed to beguile and mislead the common people against the Holy Prophet. They said: If the Qur'an were really based on the truth and Muhammad (upon whom be Allah's peace) were inviting towards a right thing, the chiefs and the elders and the noblemen of the community would have been in the forefront to accept it. How could it be that a few young boys and mean slaves only should accept a reasonable thing but the distinguished men of the nation, who are wise and experienced, and who have been held as reliable by others, would reject it? This was the deceptive reasoning by which they tried to make the common people believe that there was something wrong with the new message; that is why the ciders of the people were not believing it; therefore, they also should avoid it.
16That is, "They regard themselves as a criterion of the truth and falsehood. They think that whatever (guidance) they reject must be falsehood. But accepting them since thousands of years also were devoid of wisdom and knowledge, and the whole wisdom has now become these people's monopoly."
17"To warn the wrongdoers :" To warn of the evil end those who are being unjust to themselves and to the truth itself by disbelieving in Allah and serving others than Allah, and are involved because of this deviation of theirs in the evils of morals and deeds, which have filled human society with every kind of wickedness and injustice.