Musannaf Ibn Abi Shayba 3:2416

Abu Bakr narrated to us, he said: Abd al-Rahman ibn Mahdi narrated to us, from Sufyan, from Abu Ishaq, from Ubaydah ibn Rabi'ah, who said: I came to the Maqam (Station of Ibrahim), and there was a man with fine clothes and a pleasant scent, praying. He recited, and a man beside him was prompting him. I said: "Who is this?" They said: "Uthman."