Sa'id narrated from Qatadah that the Messenger of Allah (peace be upon him) said: "The one who has the most mercy for my Ummah among my Ummah is Abu Bakr, and the one who is the strictest and most tender-hearted regarding the matter of Allah is Umar, and the one among them with the most modesty and shyness is Uthman, and the one who knows the most about what is lawful and unlawful is Mu'adh bin Jabal, and the one who is the most expert regarding the obligations is Zayd bin Thabit, and the one who recites the Qur'an the most is Ubayy bin Ka'b." And it was said: "The one who knows the most about judgments is Ali (may Allah be pleased with him)."