Khalid bin Hakim bin Hizam narrates: Sayyiduna Abu Ubaydah bin al-Jarrah (may Allah be pleased with him) punished a man from among the inhabitants of the (dhimmi) land for something, and Sayyiduna Khalid bin al-Walid (may Allah be pleased with him) spoke to him about it. It was said to him: "Have you angered the commander?" He said: "I did not intend to anger him, but I heard the Messenger of Allah (peace and blessings be upon him) say: 'The most severely punished of people on the Day of Resurrection will be the one who was most severe in punishing people in this world.'"
Hadith Referenceالمعجم الكبير للطبراني / باب الخاء / 3809