Musannaf Ibn Abi Shayba 16:536

Abu Bakr narrated to us, he said: Ali bin Hisham narrated to us, from Ibn Abi Layla, from Thabit, who said: I was sitting with Abd al-Rahman bin Abi Layla when a man with two yellow garments, large in stature, came to him and said to him, "O Abu Isa." He said to him, "Yes." He said, "Narrate to me what you heard regarding fur garments (al-fira')." He said, "I heard my father say: I was sitting with the Prophet, may Allah bless him and grant him peace, when a man came to him and said, 'O Messenger of Allah, should I pray in fur garments?' He said, 'Where is the tanning?'"