Hadith 504731
Chapter 15: The Qur'an - كتاب القرآن
حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ عَبْدِ اللَّهِ بْنِ أَبِي بَكْرِ بْنِ حَزْمٍ، . أَنَّ فِي الْكِتَابِ الَّذِي، كَتَبَهُ رَسُولُ اللَّهِ صلى الله عليه وسلم لِعَمْرِو بْنِ حَزْمٍ " أَنْ لاَ يَمَسَّ الْقُرْآنَ إِلاَّ طَاهِرٌ.
Yahya related to me from Malik from Abdullah ibn Abi Bakr ibn Hazm that in a letter that the Messenger of Allah, may Allah bless him and grant him peace, sent to Amr ibn Hazm it said that no-one should touch the Qur'an unless he was pure.
Reference Muwatta Malik 504731
USC-MSA web (English) reference : Book 15, Hadith 1