The word “infidel” is of Latin origin and is not used by Muslims to describe those who do not share their faith. The Qur'an uses the word kafiroon (plural of kafir) to describe the people who hear the message of Islam but do not believe. The word itself means simply “those who reject.”
Muslims use the word kafir — which comes from the Arabic word for covering or hiding something (as in “covering one's heart”) — to refer to unbelievers. This word shares its root with the Arabic words for “atonement” and “penance,” implying that there is always hope that someone may later turn to God and become a believer. The doors are never closed.
The Qur'an does describe the punishment that those who reject faith will face in the Hereafter. However, Muslims are never encouraged to randomly or systematically punish, wage war against, or kill people simply because they do not believe in the message of Islam. Such behavior would be the antithesis of the Qur'anic injunction: “Let there be no compulsion in religion” (Qur'an 2:256).
A chapter of the Qur'an aptly titled Al-Kafiroon (Those Who Reject Faith) gives clear instructions to Muslims on how they should interact with those who do not believe: “Say: ‘Oh you who reject faith! I do not worship what you worship, and you will not worship what I worship. And I will never worship that which you worship, nor will you ever worship that which I worship. You have your faith, and I have mine’” (Qur'an 109:1–6). If people cannot come to any agreement through respectful discussion, the best path is to simply part ways in peace rather than seek confrontation.
The Qur'an distinguishes between people who reject faith in God outright, and those who worship false idols and deities. The Qur'an describes those people who worship idols and other gods (rather than the One Almighty God) as mushrikoon, which literally means “those who perform shirk” or associate others with God. In English, mushrikoon might be translated as “pagans” or “polytheists.”
What is shirk?
Often translated as “polytheism,” shirk is the association of idols and false deities with God Almighty. It is considered to be the worst sin in Islam, and the only one that will not be forgiven by God on the Day of Judgment.
At the time Muhammad was preaching in Mecca, the leaders and most of the people fell into this category. While they believed in the idea of One Almighty God, they fashioned idols of wood or clay and brought them food and drink in the hopes of intercession. Muhammad chastised them for worshiping objects that could do nothing to protect or help themselves, much less others. Angry at his words, the Meccans set out to torture, persecute, and attempt to destroy the Muslim community.
There are a few verses of the Qur'an that encourage the Muslims to fight firmly against the mushrikoon, but they must be understood in the terms of the historical events surrounding the revelation of these verses. The Muslims were commanded to defend themselves against “those who fight you” (Qur'an 2:190). These verses refer specifically to those Meccan tribes and their allies and others who systematically tried to destroy the Muslim community or suppress their rights to freedom of worship. In no case may a Muslim initiate aggression against a people who are not hostile; in fact, the Qur'an encourages Muslims to “deal kindly and justly with them, for Allah loves those who are just” (Qur'an 60:8).