Al-Mushrikun should not be asked to give witness

Narrated Ubaidullah bin Abdullah bin Utba:

Ibn Abbas said, "O Muslims? How do you ask the people of the Scriptures, though your Book (i.e. the Quran) which was revealed to His Prophet is the most recent information from Allah and you recite it, the Book that has not been distorted? Allah has revealed to you that the people of the scriptures have changed with their own hands what was revealed to them and they have said (as regards their changed Scriptures): This is from Allah, in order to get some worldly benefit thereby." Ibn Abbas added: "Isn't the knowledge revealed to you sufficient to prevent you from asking them? By Allah I have never seen any one of them asking (Muslims) about what has been revealed to you."

حَدَّثَنَا يَحْيَى بْنُ بُكَيْرٍ، حَدَّثَنَا اللَّيْثُ، عَنْ يُونُسَ، عَنِ ابْنِ شِهَابٍ، عَنْ عُبَيْدِ اللَّهِ بْنِ عَبْدِ اللَّهِ بْنِ عُتْبَةَ، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ قَالَ يَا مَعْشَرَ الْمُسْلِمِينَ، كَيْفَ تَسْأَلُونَ أَهْلَ الْكِتَابِ، وَكِتَابُكُمُ الَّذِي أُنْزِلَ عَلَى نَبِيِّهِ ﷺ أَحْدَثُ الأَخْبَارِ بِاللَّهِ، تَقْرَءُونَهُ لَمْ يُشَبْ، وَقَدْ حَدَّثَكُمُ اللَّهُ أَنَّ أَهْلَ الْكِتَابِ بَدَّلُوا مَا كَتَبَ اللَّهُ وَغَيَّرُوا بِأَيْدِيهِمُ الْكِتَابَ، فَقَالُوا هُوَ مِنْ عِنْدِ اللَّهِ، لِيَشْتَرُوا بِهِ ثَمَنًا قَلِيلاً أَفَلاَ يَنْهَاكُمْ مَا جَاءَكُمْ مِنَ الْعِلْمِ عَنْ مُسَاءَلَتِهِمْ، وَلاَ وَاللَّهِ مَا رَأَيْنَا مِنْهُمْ رَجُلاً قَطُّ يَسْأَلُكُمْ عَنِ الَّذِي أُنْزِلَ عَلَيْكُمْ.