Companions of the Prophet

Bukhari :: Book 5 :: Volume 57 :: Hadith 64

Narrated Marwan bin Al-Hakam:

While I was with 'Uthman, a man came to him and said, "Appoint your successor." 'Uthman said, "Has such successor been named?" He replied, "Yes, Az-Zubair." 'Uthman said, thrice, "By Allah! Indeed you know that he is the best of you."