Jami` At-Tirmidhi - جامع الترمذي
15. The Chapters On Judgements From The Messenger of Allah - كتاب الأحكام عن رسول الله صلى الله عليه وسلم
7) Chapter: What Has Been Related About 'The Judge Is Not To Pass A Judgement While He Is Angry'
'Abdur-Rahman bin Abi Bakrah narrated:
"My father wrote to 'Ubaidullah bin Abi Bakrah who was a judge: "Do not pass a judgement between two people while you are angry, for indeed I heard the Messenger of Allah (ﷺ) saying: 'The judge should not judge between two people while he is angry.'"
7) باب مَا جَاءَ لاَ يَقْضِي الْقَاضِي وَهُوَ غَضْبَانُ .
حَدَّثَنَا قُتَيْبَةُ، حَدَّثَنَا أَبُو عَوَانَةَ، عَنْ عَبْدِ الْمَلِكِ بْنِ عُمَيْرٍ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ أَبِي بَكْرَةَ، قَالَ كَتَبَ أَبِي إِلَى عُبَيْدِ اللَّهِ بْنِ أَبِي بَكْرَةَ وَهُوَ قَاضٍ أَنْ لاَ، تَحْكُمْ بَيْنَ اثْنَيْنِ وَأَنْتَ غَضْبَانُ . فَإِنِّي سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ . قَالَ أَبُو عِيسَى هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ . وَأَبُو بَكْرَةَ اسْمُهُ نُفَيْعٌ . " لاَ يَحْكُمُ الْحَاكِمُ بَيْنَ اثْنَيْنِ وَهُوَ غَضْبَانُ "