Treat us Equally

The complainer had brought his complaint to the powerful judge of the time, Umar bin Khattab. 
The involved parties were to be present and the complaint to be presented. 
The complaint was against Amir al-Mu'mineen (pbuh). Umar called unto both people, and seated himself at the chair of judge.
As per Islamic rules, both involved parties must sit by each other, so that equality may be maintained.The khalifa called the complainer, to stand before the judge.
Then he called Imam Ali (pbuh) to stand by this person:
"O Ab-al Hasan, stand by him."
As Imam Ali (pbuh) heard this comment, signs of distress appeared on his face.
The Khalifa asked:
"O Ali, aren't you willing to stand by him?"
Imam (pbuh):
"No, my distress is not for standing by him. My distress comes from the fact that you didn't comply with demands of justice, and equality. You called me with respect, calling me Ab-al Hasan. But you called on this person with his regular name. That is the cause of my distress."

The voice of human justice, p 49.
The explanation of Nahj-al Balagha
of Ibn Abi Hadeed, print of Beirut, v 4, p 18