Musnad Abu Ya'la al-Mawsili 149:36

Muhammad ibn Abd al-Rahman ibn Sahm narrated to us, Abu Ishaq al-Fazari narrated to us, from Abu Sa'd, from 'Amr ibn Murrah, from Abu al-Bakhtari al-Ta'i, from 'Aishah, who said: The Messenger of Allah (ﷺ) said: "The protection (dhimmah) of the Muslims is one; if a person of the lowest status among them grants protection to someone, it must not be violated. For every treacherous person shall have a banner by which he will be identified on the Day of Resurrection."