It was narrated that Ka'b bin 'Ujrah said:
"The Messenger of Allah mentioned a Fitnah (tribulation) that had drawn nigh. Then a man passed by with his head covered. The Messenger of Allah said: 'On that day, this man will be following right guidance.' I leapt up and took hold of 'Uthman's arms, then I turned to face the Messenger of Allah and said: 'This man?' He said: 'This man.'"
English reference: Vol. 1, Book 1, Hadith 111
Arabic reference: Book 1, Hadith 116