Musnad Ahmad 33:30

'Abd al-Razzaq narrated to us, Ibn Jurayj informed us, Abu al-Zubayr informed me that he heard Jabir ibn 'Abd Allah saying: I heard the Messenger of Allah, peace and blessings of Allah be upon him, saying: "I have been commanded to fight the people until they say: 'There is no god but Allah.' If they do that, their blood and their wealth are protected from me, except by its right, and their reckoning is with Allah."