Abu Hurairah reported,
The Messenger of Allah ﷺ said, "I will go on fighting people until they say there is no god but Allah. Once they say there is no god but Allah, their wealth and their lives are protected from me, except for what is rightfully due, and their reckoning rests with Allah." 
Ahmad 8163
Sahihوبإسناده قال رسول الله ﷺ لا أزال أقاتل الناس حتى يقولوا لا إله إلا الله فإذا قالوا لا إله إلا الله فقد عصموا مني أموالهم وأنفسهم إلا بحقها وحسابهم على الله عز وجل
This is also sahih. It is in the Individual Sahifah, number 50. The two sheikhs (Bukhari and Muslim) did not narrate it through the route of the Sahifah, nor with this wording. Bukhari narrated it, 6:80 Fath, from the narration of Saeed bin Musayab from Abu Hurairah with the wording, "I was commanded to fight the people" and so on. Likewise Muslim narrated it, 1:23 Bulaq, through the route of Ibn Musayab, similarly to Bukhari's narration.His statement, "then they have protected their wealth from me," is what is established in the three original manuscripts of the Musnad and in Jami al-Masanid. In the Individual Sahifah it reads, "then they have protected their blood and their wealth from me." The addition of the word "their blood" may be an oversight on the part of the narrator of the Sahifah, or of one of the copyists, because his subsequent statement "and their lives" already conveys that meaning.Its meaning has already occurred in the Musnad of Abu Bakr, 67, within a hadith narrated from Abu Hurairah, but narration 117 indicated that it is from Abu Hurairah's narration from Umar. It has also already occurred, 239, as a mursal narration, and it should be understood in light of that connected narration.