Musnad Ahmad 788:209

Hajjaj narrated to us, Shu'bah narrated to us, from Layth ibn Abi Sulaym, who said: I heard Abu Burdah, during the time of al-Hajjaj, narrating from Abu Musa, from the Prophet (peace and blessings of Allah be upon him), that he saw a funeral procession and they were hastening with it. He said: "Let tranquility be upon you."