Before every military expedition, the Prophet ﷺ gave clear instructions that became the foundation of Islamic rules of war - rules that were revolutionary for 7th century Arabia and remain relevant in international humanitarian law today. "Do not kill women, children, or the elderly," the Prophet commanded his armies. "Do not cut down trees or destroy crops. Do not kill livestock except for food. Do not harm monks or priests in their monasteries. Do not destroy places of worship." These rules were absolute, not conditional on the enemy's behavior, establishing moral limits on warfare that were unprecedented. The instructions to Usama bin Zaid before a military expedition exemplify the Prophet's rules of engagement: "Fight in the name of Allah and in the way of Allah. Fight those who disbelieve in Allah. Do not be deceitful. Do not be treacherous. Do not mutilate. Do not kill children." Environmental protection was mandated even during war. Abu Bakr al-Siddiq, following the Prophet's teachings, instructed his army: "Do not cut down fruit-bearing trees. Do not destroy any town. Do not slaughter sheep or camels except for food." The Prophet forbade treachery and deception in war. Treaties must be honored absolutely. He said: "Whoever has a covenant with a people must not strengthen or loosen it until its term expires."