Al-Mu'jam al-Awsat 3505 — I was riding a donkey of mine; the donkey

Al-Muhajir (may Allah have mercy on him), the freed slave of the family of Ziyad, narrates: "I was riding a donkey of mine; the donkey was so small that my feet nearly touched the ground. Suddenly, in the moonlit night, the shining bald head of the Commander of the Believers, Sayyiduna Ali bin Abi Talib (may Allah be pleased with him), appeared before me. I said: 'O Commander of the Believers, where are you heading?' He said: 'I have an errand.' I said: 'Will you not ride?' He said: 'Of course.' So I moved back onto the rear of the donkey and said: 'O Commander of the Believers, mount.' He said: 'I will not do that, for I heard the Messenger of Allah (peace and blessings be upon him) saying: "The owner of a mount has more right to sit on the front part of it, and the owner of a horse has more right to the front part of the horse."'"
Al-Tabarani (may Allah have mercy on him) said: "No one narrated this hadith from Ali bin Zayd except Yahya bin Kathir, and al-Muhajir, the freed slave of the family of Ziyad, did not narrate any hadith from Sayyiduna Ali (may Allah be pleased with him) other than this one."