Sahih Bukhari

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)