Musnad Abu Ya'la al-Mawsili 244:9

Abu Bakr narrated to us, Shababa narrated to us, from Shu'bah, from 'Amr ibn Dinar, from a man, from 'Amr ibn al-'As, who said: The Messenger of Allah (peace be upon him) said: "The lowest of them (the Muslims) may grant protection on behalf of the Muslims."