The Book of Prayers (Kitab Al-Salat)
Muslim :: Book 4 : Hadith 2128
Sulaiman b. Buraida narrated on the authority of his father that the Messenger of Allah (may peace be upon him) used to teach them when they went out to the graveyard. One of the narrators used to say this in the narration transmitted on the authority of Abu Bakr:" Peace be upon the inhabitants of the city (i. e. graveyard)." In the hadith transmitted by Zuhair (the words are):" Peace be upon you, the inhabitants of the city, among the believers, and Muslims, and God willing we shall join you. I beg of Allah peace for us and for you."