It is narrated from Sayyidah Umm Salamah (may Allah be pleased with her) that the Messenger of Allah (peace and blessings be upon him) said: "When one of you is tested with judging between the Muslims (the office of judgeship), let him never judge while he is angry; let him keep complete equality between the two parties in his gaze, his seating and his gestures; and let him not raise his voice against either of the two parties."
Hadith Referenceمسند أبي يعلى الموصلي / مسند أبي هريرة رضي الله عنه / 5867
Hadith Takhrij«قال سعيد بن محمد السناري: منكر: هذا يأتى الكلام عليه في مسند أم سلمة [برقم 6924]» «أخرجه مجمع الزوائد ومنبع الفوائد برقم: 7016، وأخرجه إتحاف الخيرة المهرة بزوائد المسانيد العشرة برقم: 4886، 4910/1، مسند ابویعلیٰ ترقیم الاثری: 5841»