Sahih al-Bukhari 5562Book 73, Hadith 18
حَدَّثَنَا آدَمُ، حَدَّثَنَا شُعْبَةُ، حَدَّثَنَا الأَسْوَدُ بْنُ قَيْسٍ، سَمِعْتُ جُنْدَبَ بْنَ سُفْيَانَ الْبَجَلِيَّ، قَالَ شَهِدْتُ النَّبِيَّ صلى الله عليه وسلم يَوْمَ النَّحْرِ فَقَالَ " مَنْ ذَبَحَ قَبْلَ أَنْ يُصَلِّيَ فَلْيُعِدْ مَكَانَهَا أُخْرَى، وَمَنْ لَمْ يَذْبَحْ فَلْيَذْبَحْ ".
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."