Sahih al-Bukhari Book 73, Hadith 17
The Prophet (ﷺ) 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 (ﷺ) seemed to accept his excuse. The man said, "I have a Jadha'a
which is to me better than two sheep." The Prophet (ﷺ) 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 (ﷺ) then went
towards two rams and slaughtered them, and the people went towards their sheep and slaughtered
them.
I heard the Prophet (ﷺ) delivering a sermon, and he said (on the Day of `Id-Allah. a), "The first thing we will do on this day of ours is that we will offer the `Id prayer, then we will return and slaughter our sacrifices; and whoever does so, then indeed he has followed our tradition, and whoever slaughtered his sacrifice (before the prayer), what he offered was just meat that he presented to his family, and that was not a sacrifice." Abu Burda got up and said, "O Allah's Messenger (ﷺ)! I slaughtered the sacrifice before the prayer and I have got a Jadha'a which is better than an old sheep." The Prophet (ﷺ) said, "Slaughter it to make up for that, but it will not be sufficient for anybody else after you."
I witnessed the Prophet (ﷺ) on the Day of Nahr. He said, "Whoever slaughtered the sacrifice before offering the `Id prayer, should slaughter another sacrifice in its place; and whoever has not slaughtered their sacrifice yet, should slaughter now."