Sahih al-Bukhari 968

Narrated Al-Bara’:

The Prophet (ﷺ) delivered the Khutba on the day of Nahr (`Id-ul-Adha) and said, “The first thing we
should do on this day of ours is to pray and then return and slaughter (our sacrifices). So anyone who
does so he acted according to our Sunna; and whoever slaughtered before the prayer then it was just
meat that he offered to his family and would not be considered as a sacrifice in any way. My uncle
Abu Burda bin Niyyar got up and said, “O, Allah’s Messenger! I slaughtered the sacrifice before the
prayer but I have a young she-goat which is better than an older sheep.” The Prophet (ﷺ) said, “Slaughter
it in lieu of the first and such a goat will not be considered as a sacrifice for anybody else after you.”