No one should touch the Qur'an except if he is tahir (pure).
~About one month before the Prophet ﷺ's death, 11 AH · 11 AH
After Najran accepted Islam, the Prophet ﷺ appointed Amr ibn Hazm al-Ansari RA as governor and religious teacher over the province. About a month before his own death, the Prophet ﷺ dictated to Amr RA a letter over a page long, full of wasiyyat (instructions) on how to teach the people, among the very last things he ﷺ ever dictated. One clause of the letter states that no one should touch the Qur'an except one who is tahir (in a state of purity).
This clause became the primary hadith evidence cited by the majority of the madhahib for the ruling that wudu is required to touch the Mushaf.
Other events recorded in 11 AH. Their order within the year is not established; use the storyline above for the sequence.
No one should touch the Qur'an except if he is tahir (pure).