Bulugh al-Maram, Book 1, Hadith 94 (In-Book)

Narrated ‘Abdullah bin Abu Bakr (rad): The book written by Allah’s Messenger for ‘Amr bin Hazm also contained: “ None except a pure person should touch the Quran”. [Reported by Malik as a Mursal and by An-Nasa’i and Ibn Hibban as Mawsul. And it is graded as Ma’lul (defective)].

وَعَنْ عَبْدِ اَللَّهِ بْنِ أَبِي بَكْرٍ رَحِمَهُ اَللَّهُ; { أَنَّ فِي اَلْكِتَابِ اَلَّذِي كَتَبَهُ رَسُولُ اَللَّهِ ‏- صلى الله عليه وسلم ‏-لِعَمْرِو بْنِ حَزْمٍ: أَنْ لَا يَمَسَّ اَلْقُرْآنَ إِلَّا طَاهِرٌ } رَوَاهُ مَالِكٌ مُرْسَلاً, وَوَصَلَهُ النَّسَائِيُّ, وَابْنُ حِبَّانَ, وَهُوَ مَعْلُولٌ.‏

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also referenced under: Book 1, Hadith 83 (English)