مُوَطَّأُ مَالِكٍ
Muwatta Malik 473
The Qur'an
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, (ﷺ), sent to Amr ibn Hazm it said that no-one should touch the Qur'an unless he was pure.
Arabic/English book reference: Book 15, Hadith 1