Musannaf Ibn Abi Shayba 28:860

Abu Khalid narrated to us, from Hajjaj, from al-Walid ibn Abi Malik, from Abd al-Rahman ibn Salama, from Abu Ubayda, who said: I heard the Messenger of Allah, may Allah bless him and grant him peace, saying: "Some of the people may grant protection on behalf of the others."