Sahih Bukhari Volume 1, Book 2, Hadith 25

حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مُحَمَّدٍ الْمُسْنَدِيُّ، قَالَ حَدَّثَنَا أَبُو رَوْحٍ الْحَرَمِيُّ بْنُ عُمَارَةَ، قَالَ حَدَّثَنَا شُعْبَةُ، عَنْ وَاقِدِ بْنِ مُحَمَّدٍ، قَالَ سَمِعْتُ أَبِي يُحَدِّثُ، عَنِ ابْنِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏"‏ أُمِرْتُ أَنْ أُقَاتِلَ النَّاسَ حَتَّى يَشْهَدُوا أَنْ لاَ إِلَهَ إِلاَّ اللَّهُ وَأَنَّ مُحَمَّدًا رَسُولُ اللَّهِ، وَيُقِيمُوا الصَّلاَةَ، وَيُؤْتُوا الزَّكَاةَ، فَإِذَا فَعَلُوا ذَلِكَ عَصَمُوا مِنِّي دِمَاءَهُمْ وَأَمْوَالَهُمْ إِلاَّ بِحَقِّ الإِسْلاَمِ، وَحِسَابُهُمْ عَلَى اللَّهِ ‏"

Narrated By 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 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."