Maliks Muwatta Book 10, Hadith Number 7.
Section : The Order to Eat Before Going Out on the Morning of the Id.
Yahya related to me from Malik from Ibn Shihab that Said al-Musayyab told him that people used to be told to eat on the day of Fitr before setting out. Malik said that he did not consider that people had to do that for Adha.