Musnad Ahmad 5:26

Muhammad ibn Ja'far narrated to us, Mu'ammar narrated to us, al-Zuhri informed us, from Abu 'Ubayd, the freed slave of 'Abd al-Rahman ibn 'Awf, who said: Then I witnessed 'Ali ibn Abi Talib, after that, on the day of an 'Eid. He began with the prayer before the sermon, and he prayed without an Adhan or an Iqamah. Then he said: "I heard the Messenger of Allah, peace and blessings of Allah be upon him, forbidding anyone from keeping anything of his sacrificial meat beyond three days."