Sahih Bukhari Volume 7, Book 68, Hadith Number 468.

Narrated By Anas : The Prophet said, “Whoever slaughtered the sacrifice before the ‘Id prayer, should repeat it (slaughter another one).” A man said “This is the day on which meat is desired.” Then he mentioned the need of his neighbors (for meat) and the Prophet seemed to accept his excuse. The man said, “I have a Jadha’a which is to me better than two sheep.” The Prophet allowed him (to slaughter it as a sacrifice). But I do not know whether this permission was general for all Muslims or not. The Prophet then went towards two rams and slaughtered them, and the people went towards their sheep and slaughtered them.