The Qadi Shurayh once said : When Ali was setting out for Siifin, he found that he was missing a coat of armour of his. When the war was over and he returned to kufah, he saw the coat in the hands of a Jew. he said to the Jew 'the armour is mine; I have not sold it or given it away' and the Jew replied 'It is my armour and it is in my hand, let us go to the Qadi'.
In the court, the Ameer-ul-Mumineen sat where the common litigants would sit and gave his case 'This armour which this Jew has, is my armour and I did not sell it nor give it away'. Qadi Shurayh asked the Jew what he said and the Jew insisted 'This is my armour and it is in my posession'. Shurayh said 'Do you have any evidence Ameer-ul-Mumi'neen?' and Ali replied 'Yes, Qanbar and my son al-Hasan will witness that the armour is mine' but the Qadi ruled that a sons testament for his father is not acceptable - even if the son was a man promised Paradise and Hasan was indeed the leader of the youth of Paradise. The Jew, having prevailed, saw the unparalelled equality in Islam and declared 'The Amir-ul-Mumineen brought me before his Qadi and the Qadi judged against him. I witness that this is the truth, and I bear witness that there is no God but Allah and I bear witness that Muhammad is His messenger (peace and blessings be upon him).
(Taken from 'The History of the Khalifah's Who took the right way' Jalal ad-din Al-Suyuti p 193-194, Ta-ha Publishers)