أَخْبَرَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، قَالَ أَنْبَأَنَا يَعْلَى بْنُ عُبَيْدٍ، عَنِ الأَعْمَشِ، عَنْ أَبِي سُفْيَانَ، عَنْ جَابِرٍ، وَعَنْ أَبِي صَالِحٍ، عَنْ أَبِي هُرَيْرَةَ، قَالاَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ أُمِرْتُ أَنْ أُقَاتِلَ النَّاسَ حَتَّى يَقُولُوا لاَ إِلَهَ إِلاَّ اللَّهُ فَإِذَا قَالُوهَا مَنَعُوا مِنِّي دِمَاءَهُمْ وَأَمْوَالَهُمْ إِلاَّ بِحَقِّهَا وَحِسَابُهُمْ عَلَى اللَّهِ ‏"‏ ‏.‏

It was narrated that Abu Hurairah said: "The Messenger of Allah [SAW] said: 'I have been commanded to fight the people until they say La ilaha illallah. If they say it, then their blood and wealth are prohibited for me, except for a right that is due, and their reckoning will be with Allah.'" Translation Not Available

Book Ref: Sunan An Nisai Book 37 Hadith 3977
Web Ref:  Sunan An Nisai Vol 5 Book 37 Hadith 3982