Funerals (Kitab Al-Jana'iz)
Dawud :: Book 20 : Hadith 3171
Narrated Thawban:
An animal was brought to the Apostle of Allah (peace_be_upon_him) while he was going with a funeral. He refused to ride on it. When the funeral was away, the animal was brought to him and he rode on it. He was asked about it. He said: The angels were on their feet. I was not to ride while they were walking. When they went away, I rode.