Musnad Ahmad 1017:51

Mu'awiyah ibn Hisham and Abu Ahmad narrated to us, they said: Sufyan narrated to us, from 'Alqamah ibn Marthad, from Sulayman ibn Buraydah, from his father, who said: The Messenger of Allah (peace and blessings of Allah be upon him) used to teach them when they went out to the graveyards, so their speaker would say: "Peace be upon you, O people of the dwellings, from among the believers and the Muslims. Indeed, we, if Allah wills, are joining you." Mu'awiyah said in his narration: "You are our predecessors, and we are your followers, and we ask Allah for well-being for us and for you."