Sahih al-Bukhari 97:29
Narrated Jundab:
That he witnessed the Prophet (ﷺ) on the Day of Nahr. The Prophet (ﷺ) offered prayer and then delivered a sermon saying, "Whoever slaughtered his sacrifice before offering prayer, should slaughter another animal in place of the first; and whoever has not yet slaughtered any, should slaughter a sacrifice and mention Allah's Name while doing so."
Reference
Sahih al-Bukhari 97:29
In-book reference
Book 97, Hadith 29
Arabic Text
حَدَّثَنَا حَفْصُ بْنُ عُمَرَ، حَدَّثَنَا شُعْبَةُ، عَنِ الأَسْوَدِ بْنِ قَيْسٍ، عَنْ جُنْدَبٍ، أَنَّهُ شَهِدَ النَّبِيَّ صلى الله عليه وسلم يَوْمَ النَّحْرِ صَلَّى ثُمَّ خَطَبَ فَقَالَ " مَنْ ذَبَحَ قَبْلَ أَنْ يُصَلِّيَ فَلْيَذْبَحْ مَكَانَهَا أُخْرَى، وَمَنْ لَمْ يَذْبَحْ فَلْيَذْبَحْ بِاسْمِ اللَّهِ ".