Musannaf Ibn Abi Shayba 3:5589

Ibn Mahdi narrated to us, from Sufyan, from his father, from Abu Ya’la, who said: Ar-Rabi’ ibn Khuthaym, when the Imam said, "Not of those who have evoked [Your] anger or of those who are astray," would say, "O Allah, forgive me, Amin."