It was narrated that 'Ali said:
"The Messenger of Allah said: 'If I were to appoint anyone as my successor without consulting anyone, I would have appointed Ibn Umm 'Abd.'" (JA)
English reference (JA): Vol. 1, Book 1, Hadith 137 (JA)
Arabic reference (JA): Book 1, Hadith 142 (JA)