Musnad Ahmad 32:708

'Abd al-Razzaq narrated to us, Ma'mar narrated to us, from Qatadah, from Anas ibn Malik, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "O Allah, forgive the Ansar, and the children of the Ansar, and the children of the children of the Ansar." Ma'mar said: And Ayyub informed me, from Abu Qilabah, from Anas, from the Messenger of Allah (peace and blessings of Allah be upon him), the like of it.