Hazrat Buraidah (may Allah be pleased with him) narrates that when the Messenger of Allah (peace and blessings be upon him) appointed someone as the leader of a group or an army, he would especially advise him to fear Allah. And he would advise him to treat the Muslims who were with him well. And he would say: Strive in the path of Allah, fight those who disbelieve in Allah, go forth and do not be treacherous, nor act deceitfully. Do not mutilate by cutting off people's hands or feet. And do not kill children.