It was narrated that 'Abdullah bin Abi Bakrah, who was a governor in Sijistan, said:"Abu Bakrah wrote to me, saying: 'I heard the Messenger of Allah [SAW] say: No one should pass two judgments on one issue, and no one should pass judgment between two disputing parties while he is angry.'"
أَخْبَرَنَا الْحُسَيْنُ بْنُ مَنْصُورِ بْنِ جَعْفَرٍ، قَالَ حَدَّثَنَا مُبَشِّرُ بْنُ عَبْدِ اللَّهِ، قَالَ حَدَّثَنَا سُفْيَانُ بْنُ حُسَيْنٍ، عَنْ جَعْفَرِ بْنِ إِيَاسٍ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ أَبِي بَكْرَةَ، - وَكَانَ عَامِلاً عَلَى سِجِسْتَانَ - قَالَ كَتَبَ إِلَىَّ أَبُو بَكْرَةَ يَقُولُ سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ " لاَ يَقْضِيَنَّ أَحَدٌ فِي قَضَاءٍ بِقَضَاءَيْنِ وَلاَ يَقْضِي أَحَدٌ بَيْنَ خَصْمَيْنِ وَهُوَ غَضْبَانُ " .
Nesai
The Book of the Etiquette of Judges • Hadith 5421