Jami` at-Tirmidhi, Hadith 1331 ⓘ
'Ali narrated: "The Messenger of Allah said to me: 'When two men come to you seeking judgement, do not judge for the first until you have heard the statement of the other. Soon you will know how to judge.'" 'Ali said: "I did not err since then."
حَدَّثَنَا هَنَّادٌ، حَدَّثَنَا حُسَيْنٌ الْجُعْفِيُّ، عَنْ زَائِدَةَ، عَنْ سِمَاكِ بْنِ حَرْبٍ، عَنْ حَنَشٍ، عَنْ عَلِيٍّ، قَالَ قَالَ لِي رَسُولُ اللَّهِ صلى الله عليه وسلم " إِذَا تَقَاضَى إِلَيْكَ رَجُلاَنِ فَلاَ تَقْضِ لِلأَوَّلِ حَتَّى تَسْمَعَ كَلاَمَ الآخَرِ فَسَوْفَ تَدْرِي كَيْفَ تَقْضِي " . قَالَ عَلِيٌّ فَمَا زِلْتُ قَاضِيًا بَعْدُ . قَالَ أَبُو عِيسَى هَذَا حَدِيثٌ حَسَنٌ .
also referenced under: Book 15, Hadith 11 (In-Book) & Volume 3, Book 13, Hadith 1331 (DarusSalam)