أَخْبَرَنِي هَارُونُ بْنُ عَبْدِ اللَّهِ، قَالَ حَدَّثَنَا عَبْدُ اللَّهِ بْنُ بَكْرٍ، قَالَ حَدَّثَنَا حَاتِمُ بْنُ أَبِي صَغِيرَةَ، عَنِ النُّعْمَانِ بْنِ سَالِمٍ، أَنَّ عَمْرَو بْنَ أَوْسٍ، أَخْبَرَهُ أَنَّ أَبَاهُ أَوْسًا قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ أُمِرْتُ أَنْ أُقَاتِلَ النَّاسَ حَتَّى يَشْهَدُوا أَنْ لاَ إِلَهَ إِلاَّ اللَّهُ ثُمَّ تَحْرُمُ دِمَاؤُهُمْ وَأَمْوَالُهُمْ إِلاَّ بِحَقِّهَا ‏"‏ ‏.‏

It was narrated from An-Nu'man bin Salim that: 'Amr bin Aws told him that his father Aws said: "The Messenger of Allah [SAW] said: 'I have been commanded to fight the people until they bear witness to La ilaha illallah (there is none worthy of worship except Allah), then their blood and their wealth become forbidden to me, except for a right that is due." Translation Not Available

Book Ref: Sunan An Nisai Book 37 Hadith 3983
Web Ref:  Sunan An Nisai Vol 5 Book 37 Hadith 3988