Imam Bukhari narrates: Nu'aim narrated to us, he said: Ibn Al-Mubarak narrated to us, from Humaid At-Tawil, from Hazrat Anas bin Malik (may Allah be pleased with him), he narrates that the Messenger of Allah ﷺ said:
"I have been commanded that I fight the people until they say La ilaha illallah, so when they say this word, and pray like us, and face our Qiblah, and slaughter like us, then their lives and their wealth become unlawful upon us, except that life and wealth upon which someone has a right, and their reckoning is upon Allah."
حَدَّثَنَا نُعَيْمٌ، قَالَ حَدَّثَنَا ابْنُ الْمُبَارَكِ، عَنْ حُمَيْدٍ الطَّوِيلِ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " أُمِرْتُ أَنْ أُقَاتِلَ النَّاسَ حَتَّى يَقُولُوا لاَ إِلَهَ إِلاَّ اللَّهُ. فَإِذَا قَالُوهَا وَصَلَّوْا صَلاَتَنَا، وَاسْتَقْبَلُوا قِبْلَتَنَا، وَذَبَحُوا ذَبِيحَتَنَا، فَقَدْ حَرُمَتْ عَلَيْنَا دِمَاؤُهُمْ وَأَمْوَالُهُمْ إِلاَّ بِحَقِّهَا، وَحِسَابُهُمْ عَلَى اللَّهِ ".
Reference: Sahih Al Bukhari 392