Treating both litigants equally in admitting them, listening to them, giving each his due until he has made his case, and attending well to both

Ibn Umar (may Allah be pleased with them both) said that the Messenger of Allah (peace and blessings be upon him) said: "People will be like a hundred camels, among which a man will not find a single one fit for riding."
(b) In the rulings of the religion all are equal; no one has precedence over another.

Sayyiduna Abdullah bin al-Zubayr (may Allah be pleased with them both) said that the Messenger of Allah (peace and blessings be upon him) decreed concerning two disputants: "Both of them are to sit before the ruler."

Sayyidah Umm Salamah (may Allah be pleased with her) narrates from the Prophet (peace and blessings be upon him) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever is entrusted with the office of judge among the Muslims, let him be just in his seating, his gestures and his glances."
(b) Abu Abdullah al-Anazi narrates with his chain: "Let him be fair in his gestures, his glances and his speech."

Umm Salamah (may Allah be pleased with her) said that the Messenger of Allah (peace and blessings be upon him) said: "Whoever is tested with the office of judge among the people, let him be fair between them in his seating, his gestures and his glances."

Umm Salamah (may Allah be pleased with her) said that the Messenger of Allah (peace and blessings be upon him) said: "Whoever is tested with the office of judge among the people, let him not raise his voice against one of the two disputants more than he raises it against the other."
This chain contains weakness.

Idris al-Awdi (may Allah have mercy on him) said: Sa'id bin Abi Burdah (may Allah have mercy on him) brought out a letter and said: This is the letter of Sayyiduna Umar (may Allah be pleased with him) to Sayyiduna Abu Musa (may Allah be pleased with him): "After praise (of Allah): Judging is a most important office and a practice that is to be followed. Understand when a case is presented to you, and spare no effort in enforcing the truth. Treat people equally before you in your gathering, so that a noble man does not hope for your leniency, and a weak man does not fear your injustice."

Yazid bin Ruman (may Allah have mercy on him) said: Sayyiduna Umar (may Allah be pleased with him) wrote to Abu Musa (may Allah be pleased with him): The people will keep fulfilling the rights of the leader as long as the leader fulfils the rights of Allah. When the leader lives in indulgence, the subjects will live likewise. It is near that people will turn away in aversion from their rulers. I seek refuge with Allah from that time overtaking me, and you, beware of rancour. Beware of desires that are followed and of the world being preferred. Establish the truth, even if it be for a single hour of the day.

Abu Rawahah Yazid bin Ayham said: Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) wrote to the people: Keep all people equal in (matters of) truth; their near one is like the distant one, and the distant one like the near one. Beware of bribery, beware of judging according to desires, and leave people alone at the time of anger. Establish the truth, even if it be for a single hour of the day.

Imam al-Sha'bi (may Allah have mercy on him) said: There was a dispute over something between Sayyiduna Umar (may Allah be pleased with him) and Sayyiduna Ubayy bin Ka'b (may Allah be pleased with him). Sayyiduna Ubayy (may Allah be pleased with him) made a claim against Sayyiduna Umar (may Allah be pleased with him), and he denied it. The two of them took their dispute to Sayyiduna Zayd bin Thabit (may Allah be pleased with him) at his house. When they entered upon him, Sayyiduna Umar (may Allah be pleased with him) said: We have come to you so that you may judge between us, and the judge is to be come to in his own house. Sayyiduna Zayd (may Allah be pleased with him) made room for him at the head of his bedding and said: O Commander of the Believers! Sit here. Sayyiduna Umar (may Allah be pleased with him) said: You have been unjust in your very first ruling; rather, I will sit with my opponent. So they sat before him. Sayyiduna Ubayy (may Allah be pleased with him) made his claim and Sayyiduna Umar (may Allah be pleased with him) denied it. Sayyiduna Zayd (may Allah be pleased with him) said to Sayyiduna Ubayy (may Allah be pleased with him): Excuse the Commander of the Believers from the oath; I would not ask this for anyone other than him. Sayyiduna Umar (may Allah be pleased with him) took the oath, and then he swore: Zayd bin Thabit will not attain (true) judgeship until Umar and an ordinary man of the Muslims are equal in his sight.

Tamim bin Salamah (may Allah have mercy on him) said: Ibn Abi Usayfir (may Allah have mercy on him) came to Judge Shurayh (may Allah have mercy on him) with a dispute (against a man), and he sat with him on the mat. He said: "Get up and sit with your opponent, for your sitting here casts suspicion." Ibn Abi Usayfir (may Allah have mercy on him) became angry, so Judge Shurayh (may Allah have mercy on him) said: "Get up and sit with your opponent; I will not abandon giving support (to the right) while I am able to do so."

Al-Sha'bi (may Allah have mercy on him) said: Sayyiduna Ali (may Allah be pleased with him) went out to the market, and there was a Christian selling a coat of mail. Sayyiduna Ali (may Allah be pleased with him) recognised the coat of mail and said: "This is my coat of mail; between me and you is the judge of the Muslims." The judge of the Muslims was Shurayh, whom Sayyiduna Ali (may Allah be pleased with him) had appointed as judge. When Judge Shurayh (may Allah have mercy on him) saw the Commander of the Believers, he stood up from his seat of judgement, seated Sayyiduna Ali (may Allah be pleased with him) in his place, and Judge Shurayh (may Allah have mercy on him) sat in front of him beside the Christian. Sayyiduna Ali (may Allah be pleased with him) said: "O Shurayh! If my opponent were a Muslim, I would have sat with him in the place of the litigant. But I heard the Messenger of Allah (peace and blessings be upon him) say: 'Do not shake hands with them, do not initiate the greeting of salam with them, do not visit their sick, do not offer the funeral prayer over them, force them to the narrow parts of the roads, and humble them as Allah has humbled them.' Judge between me and him, O Shurayh!" Shurayh (may Allah have mercy on him) said: "Speak, O Commander of the Believers." Sayyiduna Ali (may Allah be pleased with him) said: "This coat of mail of mine went missing from me a long time ago." Judge Shurayh (may Allah have mercy on him) said: "What do you say, O Christian?" The Christian said: "I do not call the Commander of the Believers a liar, but the coat of mail is mine."
Judge Shurayh (may Allah have mercy on him) said: "I do not see that it should be taken out of his hand. Do you have any evidence?" Sayyiduna Ali (may Allah be pleased with him) said: "Shurayh has spoken the truth." The Christian said: "These are the rulings of the prophets: the Commander of the Believers comes to his own judge, and his judge rules against him. By Allah, O Commander of the Believers, this coat of mail is yours. I followed you from the army, and it had fallen off your ash-coloured camel, so I took it. I bear witness that there is no god but Allah and that Muhammad (peace and blessings be upon him) is the Messenger of Allah." Sayyiduna Ali (may Allah be pleased with him) said: "Now that you have become a Muslim, it is yours." He also gave him a horse to ride. Al-Sha'bi (may Allah have mercy on him) said: I saw him fighting the polytheists.
(b) In the narration of Ibn Abdan he said: "O Shurayh! Had my opponent not been a Christian, I would have knelt before you." At the end it says: Sayyiduna Ali (may Allah be pleased with him) gifted the coat of mail to him and fixed a stipend of two thousand for him, and he was killed (as a martyr) with him on the day of Siffin.
It has also been narrated through another, weak, route from al-A'mash, from Ibrahim al-Taymi.