The Messenger of Allah said: The most merciful of my Ummah towards my Ummah is Abu Bakr; the one who adheres most sternly to the religion of Allah is 'Umar; the most sincere of them in shyness and modesty is 'Uthman; the best judge is 'Ali bin Abu Talib; the best in reciting the Book of Allah is Ubayy bin Ka'b; the most knowledgeable of what is lawful and unlawful is Mu'adh bin Jabal; and the most knowledgeable of the rules of inheritance (Fara'id) is Zaid bin Thabit. And every nation has a trustworthy guardian, and the trustworthy guardian of this Ummah is Abu 'Ubaidah bin Jarrah." (Using translation from Ibn Mājah 154)
"أرحم أُمتى بأُمَّتِى أبو بكرٍ، وأشدهم في أمرِ اللهِ عمرُ، وأصدقُهم حياءً عثمانُ، وأعلمُهم بالحلالِ والحرام معاد بن جبلٍ، وأفرضُهم زيدُ بن ثابتِ، وأقْرَؤُهم لكتابِ اللهِ أبي بن كعبٍ، ولكلِ أمةٍ أمين، وأمين هذه الأمةِ أبو عبيدةَ بن الجراحِ ".