Even before the Geneva Convention exists, Islam since 1,400 years ago had put forth various disciplines and rulings concerning warfare. Even if the Geneva Convention does not exist, the Muslims are compelled to abide by the rules Islam stipulated in tackling war. In Islam, discipline in warfare is not only to preserve the reputation of a government but it is more for adhering to the commands of the religion.
War is not for spilling blood but instead it is for upholding the truth and justice. Allah says in surah al-Baqarah verse 190 (translated as): Fight in the cause of Allah those who fight you, but do not transgress limits; for Allah loveth not transgressors.
In a hadith reported by al-Bukhari and Muslim, the Prophet s.a.w mentioned: O ye men! Do not wish for an encounter with the enemy. Pray to Allah to grant you security; (but) when you (have to) encounter them exercise patience (be firm and do not move back).
Because of that, Islam specifies that killing is only for the battlefield. Only combat those who are involved in war. The enemies who do not participate in war are neither combated nor killed.
To ensure that the emphasis on discipline during a war is being fulfilled, the Muslim scholars elaborate it in detailed and make it as the main focus so that the blood of the following groups is not spilled:
First: Women who do not join the force in war and children. In a
hadith from Ibn Umar, he said: During some of the crusades of the Prophet, a woman was found killed. Allahs Apostle then disapproved the killing of women and children. (Reported by al-Bukhari and Muslim)
Second: The elderly and sick people. They are not killed unless it is suspected that they are involved in the actions and planning of the war. This particular ruling is inferred from the case of women not assisting in the war.
Third: Those who are worshipping in houses of worship. Its evidence can be derived from the narration of Ibn Abbas, who said: When the Messenger of Allah sent out an army, he would say to them: Go out (into the battlefield of Jihad) in the name of Allah, fight in the way of Allah whoever denies Allah. Do not breach any agreements, do not steal from the possessions gained in war, do not mutilate the deads, do not kill children and the members of houses of worships. (Narrated by Ahmad, Ahmad Muhammad Syakir said that this
hadith is
hasan (good))
Al-Syaukani said (deceased in 1250 H): This
hadith provides the evidence that it is not allowed to kill anyone among the non-Muslims who only performs acts of worship such as the priests because they do not pose any threat to the Muslims. (Al-Syaukani, Nail al-Autar, vol. 8, pg. 74, Beirut: Dar al-Jil)
Fourth: The workers and peasants. The majority of
Ulama state that they are not to be killed. Its evidence is in the
hadith of Hanzalah al-Katib who said: We were with the Messenger of Allah on an expedition, and we passed by a woman who had been killed. At that time, people were gathering around her body and they let him through (to see it). He said: She did not join the war. Then he sent a man and said: Go to Khalid Ibn al-Walid and tell him: The Messenger of Allah has sent a command by saying: Do not kill children (in another narration: women) and
asif (hired servant). (Narrated by Abu Daud, Ibn Majah and Ahmad. Al-Albani verified is as
sahih (sound). Refer to Al-Albani, Silsilah al-Ahadith al-Sahihah, vol. 2, pg. 314, Riyadh: Maktabah al-Maarf li al-Nasyr).
Hired servants are those whose only duty is to prepare food, or clean the camps of the army or the likes of it. As long as they are not involved directly in the war, they are not to be killed.
Fifth: The envoys and diplomats. Abdullah bin Masud said: It pertains to the
Sunnah (practices and teachings of the Prophet) that envoys are not killed. (Reported by Abu Daud, Ahmad, al-Bazzar, Abu Yala. Their chain of reporters is considered as
hasan (al-Hathaimiy, Majma al-Zawaid, vol 5, pg. 314, Beirut: Dar al-Rayyan))
The above is an excerpt from Dr. Abiden article.