The Prophet ﷺ used to pray thirteen rakahs at night, making five of them the witr, and he would not sit during any of them except at the last one.
كان النبي ﷺ يصلي من الليل ثلاث عشرة ركعة، يوتر من ذلك بخمس، ولا يجلس في شيء إلا في آخرها.
Muslim reported it in the Book of the Prayer of Travelers (737) through several routes from Hisham bin Urwa, from his father, from Ayesha, and he mentioned it.Tirmidhi (459) added, "Then when the caller made the adhan, he would get up and pray two light rakahs."Nasai (1717) reported it through another route from Hisham, but he shortened it to her saying, "He would pray Witr with five rakahs, and would not sit except at the end of them."Tirmidhi said, Some of the people of knowledge among the companions of the Prophet ﷺ and others held the view that Witr should be prayed with five rakahs, and they said, He should not sit during any of them except at the end.He also said, I asked Abu Musab Madini about this hadith, and I said, How did the Prophet ﷺ pray Witr with nine and seven rakahs? He said, He would pray two by two, give the salam, and then pray Witr with one.I say, this interpretation contradicts what Ayesha said, that he would not sit during any of it except at the end.