Sahih al-Bukhari 7400
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."
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 ‏"‏‏.‏