Sahih al-Bukhari 7400
صحيح البخاري#7400Sahihحَدَّثَنَا 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 ".
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
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 97:29