During his Caliphate, ‘Alî b. Abî Tâlib – Allah be pleased with him - saw some armor of his with a Christian. He decided to take the matter up legally, so he took the dispute to Shurayh (the Judge).
‘Alî said, “This is my armor, and I have not sold it nor given it away.” Shurayh said to the Christian, “What have you to say about what the Amîr of the Believers claims?” The Christian replied, “It is my armor, although I do not regard the Amîr of the Believers to be a liar.”
Shurayh then turned to ‘Alî, “O Amîr of the Believers, do you have any proof (of ownership)?” ‘Alî laughed and said, “Shurayh is correct, I have no proof.” So Shurayh judged that the armor was the Christian’s. The Christian took it and began to walk away but then returned.
He proclaimed, “As for me, I testify that this is the judgment of the Prophets – the Amîr of the Believers himself takes me to his judge and the judge rules against him! I bear witness that there is no deity deserving worship but Allâh and I bear witness that Muhammad is the Messenger of Allâh. By Allâh, the armor is yours o Amîr of the Believers. I followed the army when you were on your way to the Battle of Siffîn and the armor came out of your equipment.”
‘Alî said, “If you have accepted Islâm the armor is yours.” And then he put him in his horse. Al-Sha’bî (the reporter of this incident) said, “I was later informed by those who saw this man that he fought the Khawârij (alongside ‘Alî) at the battle of Nahrawân.”
Ibn Kathîr, Al-Bidâyah wa Al-Nihâyah Vol.8 p5