Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
bayhaqi:20276Abū Zakariyyā b. Abū Isḥāq al-Muzakkī > Abū al-Ḥasan Aḥmad b. Muḥammad b. ʿUbdūs > ʿUthmān b. Saʿīd > Mūsá b. Ismāʿīl > Abūʿawānah > ʿAbd al-Malik b. ʿUmayr > ʿAbd al-Raḥman b. Abū Bakrah

[Machine] My father wrote and I wrote for him with my own hand to his son 'Ubaidullah while he was in Sijistan, I do not know what judgment you have passed between two parties while you are angry. For I heard the Messenger of Allah ﷺ saying, "No judgment should be passed between two parties while one of them is angry."  

البيهقي:٢٠٢٧٦أَخْبَرَنَا أَبُو زَكَرِيَّا بْنُ أَبِي إِسْحَاقَ الْمُزَكِّي أنبأ أَبُو الْحَسَنِ أَحْمَدُ بْنُ مُحَمَّدِ بْنِ عُبْدُوسٍ ثنا عُثْمَانُ بْنُ سَعِيدٍ ثنا مُوسَى بْنُ إِسْمَاعِيلَ ثنا أَبُوعَوَانَةَ ثنا عَبْدُ الْمَلِكِ بْنُ عُمَيْرٍ عَنْ عَبْدِ الرَّحْمَنِ بْنِ أَبِي بَكْرَةَ قَالَ

كَتَبَ أَبِي وَكَتَبْتُ لَهُ بِيَدِي إِلَى ابْنِهِ عُبَيْدِ اللهِ وَهُوَ عَلَى سَجِسْتَانَ لَا أَعْرِفَنَّ مَا حَكَمْتَ بَيْنَ اثْنَيْنِ وَأَنْتَ غَضْبَانُ فَإِنِّي سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولَ لَا يَحْكُمَنَّ حَكَمٌ بَيْنَ اثْنَيْنِ وَهُوَ غَضْبَانُ  

رَوَاهُ مُسْلِمٌ فِي الصَّحِيحِ عَنْ قُتَيْبَةَ عَنْ أَبِي عَوَانَةَ