Believe it or not, ISIL aren’t the only Muslims who attack other Muslims out of the belief that they aren’t real Muslims. I remember that there was a Muslim shopkeeper in Glasgow who was killed in April. His name was Asad Shah, and his killer claimed that he was “disrespecting Islam”. Shah happened to be the member of the Ahmadiyya sect of Islam, which is often considered to be heterodox or heretical by mainstream Muslims.
Ahmadi Muslims believe that there was another prophet after Muhammad, whose name was Mirza Ghulam Ahmad, whereas orthodox Islamic doctrine holds that Muhammad was the final prophet of Allah. As a matter of fact, Ahmad is often considered by mainstream Muslims to be one of the 30 Dajjals (in this case referring to false messiahs) that Muhammad warned will appear before the Final Hour. In Islam, there is the belief that Jesus will return to Earth during the end times, just like the Christians. In fact, Jesus is also viewed as the Messiah. Orthodox Muslims believe that Jesus is destined to actually return to Earth in the flesh in support of the caliphate, while Ahmadi Muslims the prophecy was metaphorical and that this prophecy had already been fulfilled by Ahmad, which would make him the second coming of Jesus on Earth. In Ahmad’s time, it was believed that as the Messiah his purpose was to end religious wars and condemn bloodshed. Ahamd himself believed that Islam is best propagated and championed by the written word rather than by the sword, thus he espoused the concept of “jihad of the pen” – the propagation and defense of the “truth of Islam” demonstrated through the word instead of through violence. Naturally, Ahmadi Muslims do not believe in violent jihad and believe that Islam should be spread through peaceful means instead of violence, though some Ahmadis may support jihad only as a form defensive conflict. For mainstream Muslims, however, armed jihad can be and sometimes is considered to be a valid course of action in defence of Islam, and in fact there are verses that support armed conflict against non-believers in the Quran. Why do you think Muslims who otherwise wouldn’t consider themselves jihadists would be willing to join ISIL? Ahmadi Muslims believe that Jesus was crucified, but survived the crucifixion, didn’t die and afterwards traveled to India in search of the Lost Tribes of Israel. Mainstream Muslims, by contrast, believe that Jesus was spared crucifixion by Allah, who raised him up to his countenance, leaving another man with the likeness of Jesus to be crucified by his enemies instead. It is also said that the Ahmadi Muslims are willing to deny certain hadiths that they feel contradict the Quran or the teachings of the prophet Ahmad.
It’s no surprise that the Ahmadiyya sect is considered heretical, and thus it is also no surprised that this sect is persecuted by the wider Islamic community. In Pakistan, for instance, it’s illegal for Ahmadi Muslims to call themselves Muslims and their sect is declared by the state to be un-Islamic, even though the sect they follow is a sect of Islam. Ahmadi Muslims have faced violent persecution in Pakistan for years in which they have often been killed. In the UK, not long after Asad Shah was killed, it was reported that leaflets encouraging Muslims to kill members of the Ahmadiyya sect if they refuse to convert from that sect were being distributed by the Stockwell Green mosque in London. Unsurprisingly, there are many Ahmadi Muslims in the UK who fear to admit they belong to the religion, fearing violent persecution from Pakistani Muslims communities. The Muslim Council of Britain also rejects Ahmadiyya, and consider Mirza Ghulam Ahmad to be an imposter. There are some who even think there is a campaign of hatred being directed towards them in the UK with Ahmadi-owned shops being boycotted, anti-Ahmadiyya posters being put up and Ahmadi Muslims losing their jobs and being beaten on the streets because of their religion. In Saudi Arabia, Ahmadi Muslims are apparently banned from entering the country, which is really bad because it means they are unable to the Hajj in Mecca. And in Indonesia, there is a decree issued by the Indonesian Council of Ulemas which orders them to basically stop practicing their faith, and Ahmadiyya mosques have been burned.
There is not a doubt in my mind that this persecution comes from Muslims, and that this is tied to the belief that Ahmadi Muslims are not real Muslims.