The Book of Qiyam Al-Lail (The Night Prayer) and Voluntary Prayers During the Day
20/33. Chapter:
Witr on one's mount
Sunan an-Nasai
أَخْبَرَنَا إِبْرَاهِيمُ بْنُ يَعْقُوبَ، قَالَ أَخْبَرَنِي عَبْدُ اللَّهِ بْنُ مُحَمَّدِ بْنِ عَلِيٍّ، قَالَ حَدَّثَنَا زُهَيْرٌ، عَنِ الْحَسَنِ بْنِ الْحُرِّ، عَنْ نَافِعٍ، أَنَّ ابْنَ عُمَرَ، كَانَ يُوتِرُ عَلَى بَعِيرِهِ وَيَذْكُرُ أَنَّ النَّبِيَّ صلى الله عليه وسلم كَانَ يَفْعَلُ ذَلِكَ .
It was narrated from Nafi' that : Ibn Umar used to pray witr on his camel and he mentioned that the Prophet (ﷺ) used to do that.
Reference : Sunan an-Nasa'i 1687In-book reference : Book 20, Hadith 90English translation : Vol. 2, Book 20, Hadith 1688