It was narrated that 'Abdullah bin Salimah said:
"I heard 'Ali say: 'The best of people after the Messenger of Allah is Abu Bakr, and the best of people after Abu Bakr is 'Umar.'" (ID)
English reference (ID): Vol. 1, Book 1, Hadith 106 (ID)
Arabic reference (ID): Book 1, Hadith 111 (ID)