Musannaf Ibn Abi Shayba 19:865

Abu Bakr narrated to us, he said: Abdullah ibn Bakr al-Sahmi narrated to us, from Hatim ibn Abi Saghirah, from al-Nu’man ibn Salim, that ‘Amr ibn Aws informed him, from his father, that the Messenger of Allah (may Allah bless him and grant him peace) said: "I have been commanded to fight the people until they say: 'There is no god but Allah.'"