Hadith 31-281

وَبِإِسْنادِهِ عَنْ عَلِيِ‏ عَلَيْهِ السَّلامُ قالَ: قالَ النَّبِي‏ صَلَّى اللهُ عَلَيْهِ وَآلِهِ: اُمِرتُ أَن اُقاتِلَ النَّاس حَتّى‏ يَقُولُوا: لا إِلهَ إِلاّ اللَّهِ، فَإِذا قالُوها فَقَدْ حُرِّمَ عَلَيَّ دِماؤُهُمْ وَأَمْوالُهُمْ.

According to the same documentation, on the authority of Ali (a.s.) the Prophet (S) said, “I was ordered to fight with the people until they declared There is no god but God and then their lives and property was secured.”