Narrated Anas bin Malik:
that the Messenger of Allah (ﷺ) said: "The most merciful of my nation to my nation is Abu Bakr, and the most severe of them concerning the order of Allah is 'Umar, and the most truly modest of them is 'Uthman bin 'Affan. The best reciter (of the Qur'an) among them is Ubayy bin Ka'b, the most knowledgeable of them concerning (the laws of) inheritance is Zaid bin Thabit, the most knowledgeable of them concerning the lawful and the unlawful is Mu'adh bin Jabal. Truly, every nation has a trustworthy one, and the trustworthy one of this nation is Abu 'Ubaidah bin Al-Jarrah."
English reference: Vol. 1, Book 46, Hadith 3791
Arabic reference: Book 49, Hadith 4160