Sahih Muslim Book 22, Hadith Number 4859.

Chapter : It was not permissible to eat the flesh of sacrificial animals beyond three days at the beginning of Islam, but this prohibition was abrogated, and now it is permissible.

Jabir b. ‘Abdullah reported: We did not eat the flesh of sacrificed animals beyond three (days), but then Allah’s Messenger (may peace be upon him) commanded us to make it a provision for journey and cat it (beyond three days).