Abu Da'ud أبو داود السجستاني الأزدي · The Book of the Etiquette of Judges

A man from among the Ansar came to the Messenger of Allah and said: "Will you not appoint me as you appointed so-and-so?" He said: "You will encounter selfishness after I am gone, so be patient until you meet me at the cistern (Al-Hawd)."

A group from Banu Tamim came to the Prophet . Abu Bakr said: "Appoint Al-Qa'qa' bin Ma'bad (as commander or governor)," and 'Umar said: "No, (appoint) Al-Aqra' bin Habis." They argued until they began to raise their voices, then the words were revealed: "O you who believe! Make not (a decision) in advance before Allah and His Messenger..." until the end of the Verse: "And if they had patience till you could come out to them, it would have been…

He wrote to 'Umar, to ask him (a question), and 'Umar wrote back to him telling him: "Judge according to what is in the Book of Allah. If it is not (mentioned) in the Book of Allah, then (judge) according to the Sunnah of the Messenger of Allah , and the righteous did not pass judgment concerning it, then if you wish, go ahead (and try to work it out by yourself) or if you wish, leave it. And I…