Bulugh al-Maram, Book 12, Hadith 1390 (English) ⓘ

Jundub bin Sufian (RAA) narrated, 'I witnessed (the prayer of) 'Idul Ad-ha with the Messenger of Allah and when he finished his prayer with the people, he looked at a sheep which had been sacrificed, so he said, "Anyone who has sacrificed before the prayer must sacrifice another goat instead (of the one which he slaughtered before the prayer) and if anyone has not sacrificed he should do so in Allah's name." Agreed upon.

وَعَنْ جُنْدُبِ بْنِ سُفْيَانَ ‏- رضى الله عنه ‏- قَالَ: { شَهِدْتُ اَلْأَضْحَى مَعَ رَسُولِ اَللَّهِ ‏- صلى الله عليه وسلم ‏-فَلَمَّا قَضَى صَلَاتَهُ بِالنَّاسِ, نَظَرَ إِلَى غَنَمٍ قَدْ ذُبِحَتْ, فَقَالَ: "مَنْ ذَبَحَ قَبْلَ اَلصَّلَاةِ فَلْيَذْبَحْ شَاةً مَكَانَهَا, وَمَنْ لَمْ يَكُنْ ذَبَحَ فَلْيَذْبَحْ عَلَى اسْمِ اَللَّهِ" } مُتَّفَقٌ عَلَيْه ِ (1768)‏.‏ ‏2 ‏- صحيح.‏ رواه البخاري ( 5562 )‏، ومسلم ( 1960 )‏ ( 2 )‏ واللفظ لمسلم.‏