Allah's Apostle said: "I have been ordered (by Allah) to fight against the people until they testify that none has the right to be worshipped but Allah and that Muhammad is Allah's Apostle, and offer the prayers perfectly and give the obligatory charity, so if they perform a that, then they save their lives an property from me except for Islamic laws and then their reckoning (accounts) will be done by Allah."

Narrated by Ibn Umar, in Bukhari, Volume 1, Book 2, Number 24 - Sunni Hadith