Musannaf Ibn Abi Shaybah 34413 — Reports on Abdullah bin Masud

Abu Ishaq (may Allah have mercy on him) said that Harithah bin Mudarrib (may Allah have mercy on him) said: A letter of Sayyiduna Umar (may Allah be pleased with him) was read out to us, in which was written: After praise and blessings: I have sent to you Sayyiduna Ammar bin Yasir (may Allah be pleased with him) as governor and Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) as teacher and minister. These two are among the noble companions of the Prophet (peace and blessings be upon him). And in the matter of Sayyiduna Ibn Umm Abd (may Allah be pleased with him), I have given others preference over myself.