Mujahid says that once a man struck his son with a sword and killed him. He was caught and brought before Sayyiduna Umar (may Allah be pleased with him). He said: "If I had not heard the Messenger of Allah (peace and blessings be upon him) say that retribution (qisas) is not taken from a father for (killing) his child, I would have killed you as well, and you would not have been able to get up from here."