Musnad Ahmad 32:1349

'Arim narrated to us, Mu'tamir narrated to us, he said: I heard my father narrating that Anas said: It was said to the Prophet, may Allah bless him and grant him peace: "If only you would go to 'Abdullah ibn Ubayy." So the Prophet of Allah, may Allah bless him and grant him peace, set out to him. He rode a donkey, and the Muslims set out walking, and it was salty, barren land. When the Prophet, may Allah bless him and grant him peace, came to him, he said: "Get away from me, for by Allah, the smell of your donkey has offended me." A man from the Ansar said: "By Allah, the smell of the donkey of the Messenger of Allah, may Allah bless him and grant him peace, is better in smell than you." He said: A man from his people became angry for 'Abdullah. He said: Then the companions of each of them became angry for them. He said: So there was striking between them with palm branches, hands, and sandals. He said: It reached us that it was revealed concerning them: {And if two factions among the believers should fight, then make settlement between the two} [Al-Hujurat: 9].