The Book of Sacrifices (Kitab Al-Adahi)
Muslim :: Book 22 : Hadith 4861
Abu Sa'id al-Khudri reported Allah's Messenger (may peace be upon him) having said: O people of Medina, do not eat the flesh of sacrificed animals beyond three days. Ibn al-Muthanni said: Three days. They (the Companions of the Holy Prophet) complained to the Messenger of Allah (may peace he upon him) that they had children and servants of theirs (to feed), whereupon he said: Eat, and feed others, and store, and make it a provision of food.