Musannaf Ibn Abi Shaybah

Hazrat Hujayyah narrates that Hazrat Ali (may Allah be pleased with him) used to cut off the hands of thieves and cauterize them, then imprison them and have their wounds treated. When the wound would heal, he would say, "Raise your hands," so they would raise them as if they were red male organs. Then he would say, "Who cut your hands?" They would reply, "Ali (may Allah be pleased with him) did." He would ask, "Why were they cut?" They would reply, "We committed theft." Then he would say, "O Allah, bear witness! O Allah, bear witness! You may go."