Chapter 31: The Book of Judicial Decisions
Abd al-Rahman b. Abu Bakra reported: My father dictated (and I wrote for him) to Ubaidullah b. Abu Bakra while he was the judge of Sijistan: Do not judge between two persons when you are angry, for I have heard Allah' s Messenger (ﷺ) as saying: None of you should judge between two persons when he is angry.
Sahih Muslim 1717a