It is narrated from al-Sha'bi that knowledge is taken from six of the Companions of the Messenger of Allah (peace and blessings be upon him). The knowledge of Sayyiduna Umar, Abdullah bin Mas'ud and Zayd bin Thabit (may Allah be pleased with them) resembled one another, and they would benefit from one another; while the knowledge of Sayyiduna Ali, Ubayy bin Ka'b and Abu Musa al-Ash'ari (may Allah be pleased with them) resembled one another, and they would draw from one another. The narrator says: I asked al-Sha'bi: Was Abu Musa al-Ash'ari (may Allah be pleased with him) also counted among these (great scholars)? He said: He was one of the eminent jurists.

It is narrated from al-Salt bin Bahram that a man who attended the funeral of Sayyiduna Zayd bin Thabit (may Allah be pleased with him) told me that when he was buried, Sayyiduna Ibn Abbas (may Allah be pleased with them both) stood at his grave and said: "This is how knowledge departs."