Abdullah bin Wahb عبد الله بن وهب بن مسلم القرشي · The Office of the Judge (Kitab Al-Aqdiyah)

I decide between you on the basis of my opinion in cases about which no revelation has been sent down to me.

Mu'adh bin Jabal said that when the Messenger of Allah (ﷺ) sent him to the Yemen... He then narrated the rest of the tradition to the same effect.

The Prophet (ﷺ) said: Conciliation between Muslims is permissible. The narrator Ahmad added in his version: "except the conciliation which makes lawful unlawful and unlawful lawful." Sulayman ibn Dawud added: The Messenger of Allah (ﷺ) said: Muslims are on (i.e. stick to) their conditions.

"Ka'b!" He said: "At your service, Messenger of Allah." Thereupon he made a gesture with is hand indicating: Remit half the debt due to you. Ka'b said: "I shall do so, Messenger of Allah." The Prophet (ﷺ) then said: "Get up and discharge"

The Messenger of Allah (ﷺ) said: The testimony of a deceitful man or woman, of an adulterer and adulteress, and of one who harbours rancour against his brother is not allowable.