Narrated Said bin Al-Musaiyab:
'Ali and 'Uthman differed regarding Hajj-at-Tamattu' while they were at 'Usfan (a familiar place near Mecca). 'Ali said, "I see you want to forbid people to do a thing that the Prophet did?" When 'Ali saw that, he assumed Ihram for both Hajj and 'Umra.