Musannaf Ibn Abi Shayba 27:738

Zayd ibn Hubab narrated to us, from Hisham ibn Harun al-Ansari, he said: Mu'adh ibn Rifa'ah ibn Rafi' narrated to me, from his father, he said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "O Allah, forgive the Ansar, and the descendants of the Ansar, and the descendants of their descendants, and their freed slaves, and their neighbors."