Sahih Bukhari Volume 2, Book 13, Hadith 985

حَدَّثَنَا حَامِدُ بْنُ عُمَرَ، عَنْ حَمَّادِ بْنِ زَيْدٍ، عَنْ أَيُّوبَ، عَنْ مُحَمَّدٍ، أَنَّ أَنَسَ بْنَ مَالِكٍ، قَالَ إِنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم صَلَّى يَوْمَ النَّحْرِ، ثُمَّ خَطَبَ فَأَمَرَ مَنْ ذَبَحَ قَبْلَ الصَّلاَةِ أَنْ يُعِيدَ ذَبْحَهُ فَقَامَ رَجُلٌ مِنَ الأَنْصَارِ فَقَالَ يَا رَسُولَ اللَّهِ، جِيرَانٌ لِي ـ إِمَّا قَالَ بِهِمْ خَصَاصَةٌ، وَإِمَّا قَالَ بِهِمْ فَقْرٌ ـ وَإِنِّي ذَبَحْتُ قَبْلَ الصَّلاَةِ وَعِنْدِي عَنَاقٌ لِي أَحَبُّ إِلَىَّ مِنْ شَاتَىْ لَحْمٍ‏.‏ فَرَخَّصَ لَهُ فِيهَا‏

Narrated By Anas bin Malik : Allah's Apostle offered the prayer on the day of Nahr and then delivered the Khutba and ordered that whoever had slaughtered his sacrifice before the prayer should repeat it, that is, should slaughter another sacrifice. Then a person from the Ansar stood up and said, "O Allah's Apostle! because of my neighbours (he described them as being very needy or poor) I slaughtered before the prayer. I have a young she-goat which, in my opinion, is better than two sheep." The Prophet gave him the permission for slaughtering it as a sacrifice.