Maliks Muwatta Book 49, Hadith Number 6.
Section : Prohibition against Eating with the Left Hand.
Yahya related to me from Malik from Ibn Shihab from Abu Bakr ibn Ubaydullah ibn Abdullah ibn Umar from Abdullah ibn Umar that the Messenger of Allah, may Allah bless him and grant him peace, said, “When you eat, eat with your right hand and drink with your right hand. Shaytan eats with his left hand and drinks with his left hand.”