Therefore...
Therefore, the qadi of al-Kūfah, Shurayh Ibn Harith, who was serving in that position since the times of `Umar, was found that he had bought a house for eighty Dinars. `Ali (a.s) called him and said, “I have heard that you have bought a house for eighty Dinars!” Shurayh replied, “Yes!” `Ali (a.s) looked at him in anger and said, “O Shurayh! Is it that you bought the house with someone else’s money or through ill-gotten money?
(4/58)” The requirement of this justice is that during the hearings the judge must be absolutely impartial and unbiased. Amir al-Mu’minin (a.s) was very particular about equitable treatment of the contesting parties whether they were Muslim or they were Dimmi. He gave strict instructions to the judges to follow this rule meticulously without any consideration for any one.
The author of wafiyyat al-a`yan has written that with one Dhimmi he (`Ali) went as a contesting party to the court of Shurayh the judge. Shurayh the judge stood up to receive him with due respect. The Imam (a.s) said, “This is your first injustice!” Once a person was `Ali’s guest and during the same period he made an appeal against another person in the Imam‘s court.
He told him that he was a contestant and the Prophet (a.s) has said that it is against the requirements of justice that the judge keeps one of the contesting parties as his guest and not the other. Therefore, he asked him to move away from his place. It is recorded in the books of tradition that once `Ali (a.s), during the period of `Umar, visited him in connection with a case. `Umar addressed him as Abul-Hasan and the contesting party as the opponent!
At this signs of unease came on the face of `Ali (a.s). When he was asked about his disturbance, he said that the requirement of justice is that the way of addressing the contesting parties must be equitable. Addressing the one with his kunyah and the other in a different way smacks of making difference between the two!