Mishkat al-Masabih 1435
Al-Bara’ said:
The Prophet addressed us on the day of sacrifice saying, “The first thing we do on this day of ours is to pray; then we return and sacrifice. If anyone does that he has correctly followed our custom; but if anyone makes sacrifice before praying, it is only mutton* he has got ready beforehand for his family, and has nothing to do with the rites." 

*It counts merely as ordinary food, and is not reckoned as a sacrifice.

(Bukhari and Muslim.)
وَعَنِ الْبَرَاءِ قَالَ: خَطَبَنَا النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَوْمَ النَّحْرِ فَقَالَ: «إِنَّ أَوَّلَ مَا نَبْدَأُ بِهِ فِي يَوْمِنَا هَذَا أَنْ نُصَلِّيَ ثُمَّ نَرْجِعَ فَنَنْحَرَ فَمَنْ فَعَلَ ذَلِكَ فَقَدْ أَصَابَ سُنَّتَنَا وَمَنْ ذَبَحَ قَبْلَ أَنْ نُصَلِّيَ فَإِنَّمَا هُوَ شَاةُ لَحْمٍ عَجَّلَهُ لِأَهْلِهِ لَيْسَ مِنَ النُّسُكِ فِي شَيْءٍ»