Al-Qaeda in Iraq
...The group, whose spiritual advisor and deputy leader was the Palestinian cleric Abu Anas al-Shami, cited various texts from the Qur'an and the Sunnah (traditions) of Muhammad that they perceived to be in support of their tactics. It quoted the prophet Muhammad, who said to the people of Mecca when conquering them: "By the one in whose hand the soul of Muhammad is in, I came to you with slaughter" as narrated in the books of Hadith (traditions), and quoted Muhammad as saying "Whoever slaughters a non-Muslim [at war with Islam, i.e. those perceived to be 'enemy occupiers'] sincerely for the sake of Allah, Allah will make hellfire prohibited upon him." Other verses of the Qur'an call Muslims to fight invading non-Muslims and even behead them, such where Allah says in the Qur'an, "when you meet the non-Muslim [enemies in battle] strike their necks."