Sayyiduna Wa'il bin Hujr (may Allah be pleased with him) said: I was with the Prophet (peace and blessings be upon him), and two men came disputing. One of them said: "This man seized my land in the Jahiliyyah." He was Imru' al-Qays bin Abis al-Kindi (may Allah be pleased with him), and his opponent was Rabi'ah. The other said: "It is my land; I cultivate it." He (peace and blessings be upon him) said: "Do you have evidence?" He said: "No." He (peace and blessings be upon him) said: "Then you are owed his oath." He said: "He does not care what he swears upon." He (peace and blessings be upon him) said: "There is nothing for you except that." When he went to take the oath, he (peace and blessings be upon him) said: "If he swears wrongfully, he will meet Allah while He is angry with him."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب آداب القاضي / 20468
Sayyiduna Ali (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "When two men bring a dispute to you, do not judge for the first until you hear what the other has to say; then you will see how to judge." He said: I continued judging in this way ever after.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب آداب القاضي / 20469