Narrated Marwan bin Al-Hakam
`Uthman bin `Affan was afflicted with severe nose-bleeding in the year when such illness was prevelant and that prevented him from performing Hajj, and (because of it) he made his will. A man from Quraish came to him and said, "Appoint your successor." `Uthman asked, "Did the people name him? (i.e. the successor) the man said, "Yes." `Uthman asked, "Who is that?" The man remained silent. Another man came to `Uthman and I think it was Al-Harith. He also said, "Appoint your successor." `Uthman asked, "Did the people name him?" The man replied "Yes." `Uthman said, "Who is that?" The man remained silent. `Uthman said, "Perhaps they have mentioned Az-Zubair?" The man said, "Yes." `Uthman said, "By Him in Whose Hands my life is, he is the best of them as I know, and the dearest of them to Allah's Messenger (ﷺ)."
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."
Narrated Jabir
The Prophet (ﷺ) said, "Every prophet used to have a Hawari (i.e. disciple), and my Hawari is Az-Zubair bin Al-`Awwam."
Narrated `Abdullah bin Az-Zubair
During the battle of Al-Ahzab, I and `Umar bin Abi-Salama were kept behind with the women. Behold! I saw (my father) Az-Zubair riding his horse, going to and coming from Bani Quraiza twice or thrice. So when I came back I said, "O my father! I saw you going to and coming from Bani Quraiza?" He said, "Did you really see me, O my son?" I said, "Yes." He said, "Allah's Messenger (ﷺ) said, 'Who will go to Bani Quraiza and bring me their news?' So I went, and when I came back, Allah's Apostle mentioned for me both his parents saying, "Let my father and mother be sacrificed for you."'
Narrated `Urwa
On the day of the battle of Al-Yarmuk, the companions of the Prophet (ﷺ) said to Az-Zubair, "Will you attack the enemy vigorously so that we may attack them along with you?" So Az-Zubair attacked them, and they inflicted two wounds over his shoulder, and in between these two wounds there was an old scar he had received on the day of the battle of Badr When I was a child, I used to insert my fingers into those scars in play.