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.
أَنَّ فِي الْكِتَابِ الَّذِي كَتَبَهُ رَسُولُ اللَّهِ ﷺ لِعَمْرِو بْنِ حَزْمٍ أَنْ لاَ يَمَسَّ الْقُرْآنَ إِلاَّ طَاهِرٌ