Sayyiduna Anas bin Malik (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: "The most merciful of my Ummah towards my Ummah is Abu Bakr, the strictest regarding Allah’s commands is Umar, the most modest is Uthman, the one who recites Allah’s Book the most is Ubayy ibn Ka’b, the most knowledgeable regarding the laws of inheritance (or knowledge of inheritance) is Zayd ibn Thabit, and the one who knows the most about what is lawful and unlawful is Mu’adh ibn Jabal. Be aware! Every nation has a trustworthy one, and the trustworthy one of this Ummah is Abu Ubaidah ibn al-Jarrah."