"The messenger of Allah (peace be upon him) used to pray atop his mount while travelling, facing whatever direction it was facing." (One of the narrators) Malik said: "Abdullah bin Dinar said: and Ibn Umar used to do likewise".
Sunan an-Nasa'i Book 9, Hadith 2
← Previous Hadith Al Bara bin Azib said: The messenger of Allah (peace be upon him) came to Al-Madinah and prayed toward Bait-al-Maqdis for sixteen months, then he was commanded to pray toward the Ka'bah. A man who had prayed with the prophet (peace be upon him)passed by some of the Ansar and said: "I bear witness that the messenger of Allah (peace be upon him) has been commanded to face toward the Ka'bah. So they turned to face the Ka'bah".

Sunan an-Nasa'i Book 9, Hadith 1 Next Hadith → "The messenger of Allah (peace be upon him) used to pray atop his mount while traveling, facing whatever direction it was facing, and he would pray witr atop it, but he did not pray the prescribed prayers atop it ".

Sunan an-Nasa'i Book 9, Hadith 3