Musnad Abu Ya'la al-Mawsili 155:198

Abu Sa'id al-Ashajj narrated to us, Abu Khalid al-Ahmar narrated to us, from Hajjaj, from Qatadah, from Muhammad ibn Sirin, from Abu Hurayrah, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Whoever eats while forgetting, or drinks while forgetting, then it is only a provision that Allah has provided him."