Abu Firas said: Umar bin al-Khattab (may Allah be pleased with him) addressed us and said: "O people! I have not sent my governors to you to beat your skins or to take your wealth; rather, I have sent them to teach you your religion and your Sunnah. Whoever is treated otherwise, let him bring it to me, and I will have retaliation taken from him." Amr bin al-As (may Allah be pleased with him) stood up and said: "O Commander of the Believers! If someone strikes some of his subjects to discipline them, will retaliation be taken from him?" He said: "Yes, by Allah! I will take retaliation from him, for I saw the Messenger of Allah (peace and blessings be upon him) give retaliation against himself."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنايات / 16017