Sahih Muslim , Book 35, Hadith 34 (In-Book) ⓘ

Abu Ubaid reported: I was with 'Ali b. Abi Talib on the occasion of the 'Id day. He started with the 'Id prayer before delivering the sermon, and said: Allah's Messenger forbade us to eat the flesh of our sacrificial animals beyond three days.

حَدَّثَنِي عَبْدُ الْجَبَّارِ بْنُ الْعَلاَءِ، حَدَّثَنَا سُفْيَانُ، حَدَّثَنَا الزُّهْرِيُّ، عَنْ أَبِي عُبَيْدٍ، قَالَ شَهِدْتُ الْعِيدَ مَعَ عَلِيِّ بْنِ أَبِي طَالِبٍ فَبَدَأَ بِالصَّلاَةِ قَبْلَ الْخُطْبَةِ وَقَالَ إِنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم نَهَانَا أَنْ نَأْكُلَ مِنْ لُحُومِ نُسُكِنَا بَعْدَ ثَلاَثٍ ‏.‏