Sahih al-Bukhari 3718
Sahih al-Bukhari · Book 62: Companions of the Prophet · The merits of Az-Zubair bin Al-'Awwam رضي الله عنه
Narrated Marwan bin Al-Hakam:
حَدَّثَنِي عُبَيْدُ بْنُ إِسْمَاعِيلَ ، حَدَّثَنَا أَبُو أُسَامَةَ ، عَنْ هِشَامٍ ، أَخْبَرَنِي أَبِي ، سَمِعْتُ مَرْوَانَ ، كُنْتُ عِنْدَ عُثْمَانَ ، أَتَاهُ رَجُلٌ فَقَالَ اسْتَخْلِفْ. قَالَ وَقِيلَ ذَاكَ قَالَ نَعَمْ، الزُّبَيْرُ. قَالَ أَمَا وَاللَّهِ إِنَّكُمْ لَتَعْلَمُونَ أَنَّهُ خَيْرُكُمْ. ثَلاَثًا.
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."