Musannaf Ibn Abi Shaybah

Hazrat Muhammad bin Ubaidullah narrates that Hazrat Umar appointed Saib bin Aqra as the governor of Mada'in. One day, he was sitting in his assembly when a copper tray was brought to him, which was made in the shape of a man's hand. Saib bin Aqra put his hand in the tray and took a handful, saying, "This is mine; Allah has granted this to me." Then he wrote a letter to Hazrat Umar regarding this matter, so Hazrat Umar replied, "You are merely a governor of the Muslims; deposit all of this into the Muslims' treasury (Bait-ul-Mal)."