Both branches of Islam believe the other has strayed so far from the path that its followers are infidels.

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The Sufi sheikhs, or holy men, preached that a true Muslim could not tolerate the rule of foreign infidels.

ECONOMIST: Special

While Pew's study will likely cheer the hearts of atheists, the rapid rise of religiously unaffiliated Americans hasn't necessarily spawned a generation of infidels.

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In the case of digital cameras, preaching to the infidels would mean, for example, trying to create a digital camera for high-end portrait photographers.

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Now he has reversed that stance, warning against branding fellow-Muslims as infidels.

ECONOMIST: Public repentance

Those that imply that God used evolution are infidels at worse, or clowns at best, that refuse to learn the truth of Genesis.

FORBES: Evolution bugs people

This prompted Ibn Kathir to conclude that they were infidels (kuffar).

CENTERFORSECURITYPOLICY: Center For Security Policy

Lennon said the man he targeted was another man who he said was part of an EDL splinter group, the North East Infidels, intent on causing trouble.

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She and other Islamic feminists believe that by fighting for women's rights within Islam, using the very same texts and doctrines that have proved so oppressive, women may be able to push through reform without being told that they have been indoctrinated by Western infidels.

ECONOMIST: The Middle East