From Sahih Bukhari (Hadith 3671):
Narrated Muhammad bin Al-Hanafiya:I asked my father (`Ali bin Abi Talib), "Who are the best people after Allah's Messenger (ﷺ) ?" He said, "Abu Bakr." I asked, "Who then?" He said, "Then `Umar. " I was afraid he would say "Uthman, so I said, "Then you?" He said, "I am only an ordinary person
Reference: Bukhari 3671