عَنْ نَافِعٍ عَنْ ابْنِ عُمَرَ رَضِيَ اللَّهُ عَنْهُ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ كَانَ يُصَلِّي عَلَى رَاحِلَتِهِ وَيُوْتِرُ عَلَيْهَا وَيَذْكُرُ ذَلِكَ عَنِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ
Sayyiduna Abdullah bin Umar (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) used to offer voluntary prayers on his mount, and he would also perform Witr on it.