Sunan an Nasai 4423
The Book of ad-Dahaya (Sacrifices)
أَخْبَرَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، قَالَ أَنْبَأَنَا عَبْدُ الرَّزَّاقِ، قَالَ حَدَّثَنَا مَعْمَرٌ، عَنِ الزُّهْرِيِّ، عَنْ سَالِمٍ، عَنِ ابْنِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم نَهَى أَنْ تُؤْكَلَ لُحُومُ الأَضَاحِي بَعْدَ ثَلاَثٍ .
It was narrated from Ibn 'Umar that:the Messenger of Allah forbade eating the meat of sacrificial animals after three days" (Sahih)
Grading: Abu Ghuddah: Sahih · Al-Albani: Sahih · Zubair Ali Zai: Sahih Muslim
Text from the public-domain hadith-api dataset. Numbering follows that dataset and can differ by a few from some printed editions — check the wording, not only the number.