(Imām Bukhārī narrates): Ismail narrated the hadith to us, he said: Imam Malik narrated the hadith to me, from Abu Bakr bin Umar bin Abdur Rahman bin Abdullah bin Umar bin al-Khattab, from Sa'id bin Yasar, he narrated that
I was going by night with Hazrat Abdullah bin Umar (Allāh be pleased with them both) on the road to Makkah, so Sa'id said: When I feared the coming of morning, I got down from my mount, then I offered Witr, then I caught up with him, so Hazrat Abdullah bin Umar asked: Where were you? I said: I feared the coming of morning, so I got down from my mount and offered Witr. So Hazrat Abdullah said: Is there not for you an excellent example in the Messenger of Allāh ﷺ? I said: Why not! By Allāh! He said: Then indeed the Messenger of Allāh ﷺ used to offer Witr upon a camel.
Reference: Sahih Al Bukhari 999