Musnad Abu Ya'la al-Mawsili 8:8

Zuhayr narrated to us, Sulayman ibn Hayyan Abu Khalid al-Ahmar narrated to us, from al-Hajjaj, from al-Walid ibn Abi Malik, from Abd al-Rahman ibn Maslamah, who said: A man granted protection to some people while he was with Khalid ibn al-Walid, Abu Ubaydah, and Amr ibn al-As. Khalid and Amr said, "We do not grant protection to those whom he has granted protection." Abu Ubaydah ibn al-Jarrah said, "I heard the Messenger of Allah, peace and blessings of Allah be upon him, say: 'Some of the Muslims grant protection on behalf of all the Muslims.'"