Sa'id narrated that Muhammad bin Thabit 'Abdi narrated from Qatadah, who said about the Messenger of Allah (peace be upon him): "The most merciful to my Ummah is Abu Bakr, the most strict and the softest-hearted is 'Umar, the most modest and shy is 'Uthman, the most knowledgeable about what is lawful and unlawful is Mu'adh bin Jabal, the most knowledgeable about the obligatory duties is Zayd bin Thabit, and the one who recites the Qur'an the most is Ubayy bin Ka'b."