Sahih Muslim Book 022, Hadith Number 4824.
Chapter : The proper time for sacrifice.
Al-Bara' b. 'Azib reported that his maternal uncle Abu Burda b. Niyar sacrificed his animal earlier than the Holy Prophet (may peace be upon him) had sacrificed. Thereupon he said: Apostle of Allah, it is the day of meat and it is not desirable (to have longing for it and not to make use of it immediately), so I hastened in offering my animal as a sacrifice, so that I might feed my family and neighbours and my kith and kin. Thereupon Allah's Messenger (may peace be upon him) said: Offer again your sacrifice. He said: Messenger of Allah, I have a small milch goat of less than one year, and that is better than two dry goats (from which only) meat (can be acquired). Thereupon he said: That is better than the two animals of sacrifice on your behalf, and the sacrifice of a goat, of less than six months shall not be accepted as a sacrifice on behalf of anyone after your (sacrifice).