Sahih Muslim
The Book of Drinks (Kitab Al-Ashriba)
Book Number: 023 / Hadith Number: 5008
Ibn 'Umar reported Allah's Messenger (may peace be upon him) as saying: When any one of you intends to eat (meal), he should eat with his right hand. and when he (intends) to drink he should drink with his right hand, for the Satan eats with his left hand and drinks with his left hand.