Sunan Ibn Majah, Volume 2, Book 5, Hadith 1200 (DarusSalam) ⓘ

It was narrated that Sa’eed bin Yasar said: “I was with Ibn ‘Umar and I lagged behind and prayed Witr. He said: ‘What kept you?’ I said: ‘I was praying Witr.’ He said: ‘Do you not have the best of examples in the Messenger of Allah?’ I said: ‘Of course.’ He said: ‘The Messenger of Allah used to pray Witr while riding his camel.’”

حَدَّثَنَا أَحْمَدُ بْنُ سِنَانٍ، حَدَّثَنَا عَبْدُ الرَّحْمَنِ بْنُ مَهْدِيٍّ، عَنْ مَالِكِ بْنِ أَنَسٍ، عَنْ أَبِي بَكْرِ بْنِ عُمَرَ بْنِ عَبْدِ الرَّحْمَنِ بْنِ عَبْدِ اللَّهِ بْنِ عُمَرَ بْنِ الْخَطَّابِ، عَنْ سَعِيدِ بْنِ يَسَارٍ، قَالَ كُنْتُ مَعَ ابْنِ عُمَرَ فَتَخَلَّفْتُ فَأَوْتَرْتُ فَقَالَ مَا خَلَفَكَ قُلْتُ أَوْتَرْتُ ‏.‏ فَقَالَ أَمَا لَكَ فِي رَسُولِ اللَّهِ ـ صلى الله عليه وسلم ـ أُسْوَةٌ حَسَنَةٌ قُلْتُ بَلَى ‏.‏ قَالَ فَإِنَّ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ كَانَ يُوتِرُ عَلَى بَعِيرِهِ ‏.‏