Sa‘d b. Hisham said

I went to ‘A’isha and said, “Mother of the faithful, tell me about the nature of Allah's Messenger ﷺ.” She asked, “Do you not recite the Qur’an?” On my replying that I certainly did, she said, “The Prophet’s nature was the Qur’an.”* I said, “Mother of the faithful, tell me about the witr of Allah's Messenger ﷺ.” She replied, “I used to prepare his toothstick and his water for ablution, and Allah would rouse him to the extent He wished during the night. He would use the toothstick, perform ablution, and pray nine rak'as, sitting only during the eighth of them, then he would make mention of Allah, praise and supplicate Him, then he would get up without uttering the salutation and pray the ninth. After that he would sit, make mention of Allah, praise and supplicate Him, then utter a salutation loud enough for me to hear. He would then pray two rak'as sitting after uttering the salutation, and that made eleven rak'as, sonny. But when Allah's Messenger ﷺ grew old and became fleshy he observed a witr of seven, doing in the two rak'as, as he had done formerly, and that made nine, sonny. When Allah’s prophet prayed a prayer he liked to keep on observing it, but when sleep or pain made it impossible for him to get up during the night; he prayed twelve rak'as during the day. I am not aware of Allah’s prophet having recited the whole Qur’an in a night, or praying through a whole night till morning, or fasting a complete month, except Ramadan.” *i.e. the good characteristics included in the Qur’an were shown by the Prophet (ﷺ) in his own life. Muslim transmitted it.