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كتاب الاعتصام بالكتاب والسنة
96  
Holding Fast to the Qur'an and Sunnah
(25)
Chapter: “Do not ask the people of the Scripture about anything.”
(25)
باب قَوْلِ النَّبِيِّ صلى الله عليه وسلم ‏"‏ لاَ تَسْأَلُوا أَهْلَ الْكِتَابِ عَنْ شَىْءٍ ‏"‏
Sahih al-Bukhari 7361
Narrated Humaid bin 'Abdur-Rahman that he heard Mu'awiya talking to a group of people from Quraish at Al-Madina, and on mentioning Ka'b Al-Ashbar, he said, "He was one of the most truthful of those who used to talk about the people of the Scripture, yet we used to detect certain faults in his information."
وَقَالَ أَبُو الْيَمَانِ أَخْبَرَنَا شُعَيْبٌ، عَنِ الزُّهْرِيِّ، أَخْبَرَنِي حُمَيْدُ بْنُ عَبْدِ الرَّحْمَنِ، سَمِعَ مُعَاوِيَةَ، يُحَدِّثُ رَهْطًا مِنْ قُرَيْشٍ بِالْمَدِينَةِ، وَذَكَرَ كَعْبَ الأَحْبَارِ فَقَالَ إِنْ كَانَ مِنْ أَصْدَقِ هَؤُلاَءِ الْمُحَدِّثِينَ الَّذِينَ يُحَدِّثُونَ عَنْ أَهْلِ الْكِتَابِ، وَإِنْ كُنَّا مَعَ ذَلِكَ لَنَبْلُو عَلَيْهِ الْكَذِبَ‏.‏
Reference : Sahih al-Bukhari 7361
In-book reference : Book 96, Hadith 88
USC-MSA web (English) reference : Vol. 1, Book 92, Hadith 459
  (deprecated numbering scheme)