Allah says in the Qur'an: "if any one slew a person - unless it be for murder or for spreading mischief in the land - it would be as if he slew the whole people: and if any one saved a life, it would be as if he saved the life of the whole people..." (Qur'an 5:32)
"Fight in the cause of Allah those who fight you, but do not transgress limits; for Allah loveth not transgressors. (Qur'an 2:190)
Explanation of this verse from Ibn Kathir's Tafsir: {but transgress not the limits. Truly, Allah likes not the transgressors.} This Ayah means, `Fight for the sake of Allah and do not be transgressors,' such as, by committing prohibitions. Al-Hasan Al-Basri stated that transgression (indicated by the Ayah), "includes mutilating the dead, theft (from the captured goods), killing women, children and old people who do not participate in warfare, killing priests and residents of houses of worship, burning down trees and killing animals without real benefit.'' This is also the opinion of Ibn `Abbas, `Umar bin `Abdul-`Aziz, Muqatil bin Hayyan and others.
Sayings of Prophet Muhammad (peace be upon him)
Ibn `Abbas says: The Messenger of Allah, when dispatching his troops, would tell them, " ..Do not behave treacherously, nor misappropriate war-booty, nor mutilate [those whom you kill], nor kill children, nor the people in cloisters." [Narrated by Ahmad, Tirmidhi (who graded it hasan sahih ]).
Yahya related to me from Malik from Nafi from Ibn Umar that the Messenger of Allah, may Allah bless him and grant him peace, saw the corpse of a woman who had been slain in one of the raids, and he disapproved of it and forbade the killing of women and children. (Maliks Muwatta, Book 021, Hadith Number 009.)
It is narrated by Ibn 'Umar that a woman was found killed in one of these battles; so the Messenger of Allah (may peace be upon him) forbade the killing of women and children (Muslim, Book 019, Hadith Number 4320)
Some Examples of The Mercy Of Prophet Muhammad (peace be upon him)
The Conquest of Mecca
..In 630 C.E. the Prophet Muhammad decided to take an army of 10,000 towards Mecca. Once the Muslims had reached Mecca, the leaders of Quraysh surrendered. As a result the Prophet Muhammad announced:
Those who shelter in the Ka’ba are safe; those who shelter in the house of Abu Sufyan are safe, and those who remain confined to their houses are also safe.
Abu Sufayan was a leader of Quraysh and one of the ardent enemies of the Prophet Muhammad. The Meccans were afraid about the impending conquest of their city because the Arabs had lived by the law of retaliation and there was a fear that Muslims would take revenge for the persecution of the Muslims and the losses in subsequent battles. When the Prophet Muhammad and the Muslims entered the area of the Kaba, he announced clemency for everyone in Mecca who no longer wished to fight the Muslims:
This day no reproach shall be on you. God will forgive you; He is the Most Merciful of the Merciful. You can go away!
Many of the Meccans, who were expecting some sort of punishment, were surprised by the Prophet’s statement and some decided to become Muslim. Thus, the conquest of Mecca was bloodless and ended years of warfare and violence between Quraysh and the Muslims.
This event is significant for Muslims because it demonstrates the character of the Prophet Muhammad. He could have exacted revenge, in accordance with the traditions of the Arabs, but instead he showed mercy on the Meccans. This is an important reminder for Muslims even to the present day about how conflict should be addressed. Finally, the conquest was a defining moment because it established Islam on the Arabian Peninsula, from there it spread to become a major world religion. (from http://insideislam.wisc.edu/2012/04/important-events-the-conquest-of-mecca/)
Enemy Becomes A Friend
http://islamstory.com/en/node/30006
