Sahih Muslim Book 6, Hadith Number 2541.

Chapter : Forbiddance to observe fast on ‘Id-ul-Fitr and ‘Id-al-Adha.

Ibn Ka’b b. Malik reported on the authority of his father that the Messenger of Allah (may peace be upon him) sent him and Aus b. Hadathan during the days of Tashriq to make this announcement: None but the believer would be admitted into Paradise, and the days of Mina’ are the days meant for eating and drinking.