Musannaf Ibn Abi Shayba 33:915

Affan narrated to us, he said: Mahdi narrated to us, he said: Ghaylan ibn Jarir narrated to us, from Mutarrif, who said: I saw in a dream as if I had gone out intending [to attend] the Friday prayer. I came upon the graves of the tribe, and behold, the people of the graves were sitting. I began to greet them and pass by. They said, "O servant of Allah, where are you heading?" I said, "I am heading to the Friday prayer." I then said, "Do you know what the Friday prayer is?" They said, "Yes, and we know what the birds say on that day." I said, "What do the birds say on that day?" They said, "They say: Peace, peace; a righteous day."