Musnad Ahmad 32:961

Waki’ narrated to us, from Sufyan, from Khalid al-Hadhdha’, from Abu Qilabah, from Anas, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The most merciful of my Ummah is Abu Bakr, and the most severe of them regarding the religion of Allah is ‘Umar, and the most truthful of them in modesty is ‘Uthman, and the most knowledgeable of them regarding the lawful and the unlawful is Mu’adh ibn Jabal, and the best reciter of them of the Book of Allah is Ubayy, and the most knowledgeable of them regarding the laws of inheritance is Zayd ibn Thabit. And for every nation there is a trustworthy one, and the trustworthy one of this nation is Abu ‘Ubaydah ibn al-Jarrah."