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Surah 3. Aal-Imran
Ayah 61 - 63
61فَمَنْ حَآجَّكَ فِيهِ مِنۢ بَعْدِ مَا جَآءَكَ مِنَ ٱلْعِلْمِ فَقُلْ تَعَالَوْا۟ نَدْعُ أَبْنَآءَنَا وَأَبْنَآءَكُمْ وَنِسَآءَنَا وَنِسَآءَكُمْ وَأَنفُسَنَا وَأَنفُسَكُمْ ثُمَّ نَبْتَهِلْ فَنَجْعَل لَّعْنَتَ ٱللَّهِ عَلَى ٱلْكَـٰذِبِينَ
62إِنَّ هَـٰذَا لَهُوَ ٱلْقَصَصُ ٱلْحَقُّ ۚ وَمَا مِنْ إِلَـٰهٍ إِلَّا ٱللَّهُ ۚ وَإِنَّ ٱللَّهَ لَهُوَ ٱلْعَزِيزُ ٱلْحَكِيمُ
63فَإِن تَوَلَّوْا۟ فَإِنَّ ٱللَّهَ عَلِيمٌۢ بِٱلْمُفْسِدِينَ
[61-63] After the coming of this knowledge to you, if anyone argues with you about this matter, say, O Muhammad, "Come, let us both gather together and also bring our children and your children, our women and your women, and then pray to Allah and invoke Him to lay the liars under His curse."55 These narratives are absolutely true and the fact is that there is no deity save Allah; indeed Allah is All Mighty and All-Wise. Then if they turn away (from accepting the challenge) it will be a clear proof of their mischief and Allah has full knowledge of the mischief-makers.
55This method of settling the dispute was proposed to show conclusively that the members of the deputation of Najran were behaving obdurately. As a matter of fact, they had no answer to the things pointed out in the above discourse and could not bring any authority even from their own Scriptures to justify and support their beliefs under discussion. They could not, therefore, assert with full conviction that their beliefs conformed to the fact and were not false. Besides this, when they observed closely the character and the teachings and the works of the Holy Prophet, the majority of the members of the deputation were so impressed that they became convinced in their hearts of his Prophethood; or at least, they could not reject it boldly. That is why they did not accept the challenge: "If you really believe in the truth of your creed, you should pray with us to Allah and invoke His curse on those who say false things about Christ." The fact that they declined to accept the challenge showed plainly to the whole of Arabia that the religious leaders and priests of the Christians of Najran who were known far and wide for their piety, professed beliefs about which they themselves were not sure.