Umar bin Uthman (may Allah have mercy on him) said: My grandfather narrated to me that when Sayyiduna Uthman (may Allah be pleased with him) sat in his seat of judgement and two men came to him with a dispute, he would say to one: Go and call Sayyiduna Ali (may Allah be pleased with him). And he would say to the other: Bring Talhah and al-Zubayr (may Allah be pleased with them both) and a group of the Companions (may Allah be pleased with them) of the Prophet (peace and blessings be upon him). Then he would say to the two disputants: Speak. Then he would turn to the people and say: What do you say? If their opinion agreed with his, he would pass judgement; otherwise he would look into it further. The two would then stand up and shake hands.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب آداب القاضي / 20326