Bukhari, Volume 1, Book 2, Number 25:
Narrated Ibn 'Umar:
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 all that, then they save their lives and property from me except for Islamic laws and then their reckoning (accounts) will be done by Allah."Sahih Muslim, Book 031, Number 5917:
...Ali went a bit and then halted and did not look about and then said in a loud voice: Allah's Messenger, on what issue should I fight with the people? Thereupon he (the Prophet) said: Fight with them until they bear testimony to the fact that there is no god but Allah and Muhammad is his Messenger, and when they do that then their blood and their riches are inviolable from your hands but what is justified by law and their reckoning is with Allah.