Musnad Abu Ya'la al-Mawsili 108:42

Narrated to us ‘Abd al-A‘la, narrated to us Mu‘tamir, narrated to us Abu Isma‘il, from Abu al-Zubayr and al-Walid ibn ‘Abd Allah ibn Abi Mughith, from Jabir, that the Prophet of Allah, may Allah bless him and grant him peace, said: "Do not give permission to anyone who does not begin with the greeting (salam)."