Sunan At-Tirmidhi

Some men who were companions of Mu'adh narrated from Mu'adh that the Messenger of Allah (ﷺ) sent Mu'adh to Yemen, so he (ﷺ) said:""How will you judge?"" He said: ""I will judge according to what is in Allah's Book."" He said: ""If it is not in Allah's Book ?"" He said: ""Then with the Sunnah of the Messenger of Allah (ﷺ)."" He said: ""If it is not in the Sunnah of Messenger of Allah (ﷺ)?"" He said: ""I will give in my view."" He said: ""All praise is due to Allah, the One Who made the messenger of the Messenger of Allah suitable