Musnad Ahmad 32:2011

Hajjaj narrated to us, Shu'bah narrated to me, he said: I heard Qatadah, he said: Anas ibn Malik narrated to us, that the Messenger of Allah, peace and blessings of Allah be upon him, used to say: "O Allah, indeed the good is the good of the Hereafter," or he said: "O Allah, there is no good except the good of the Hereafter, so forgive the Ansar and the Muhajirah (the Emigrants)." Shu'bah said: "Qatadah used to say this in his sermons."