Al-Bara’ reported God’s Messenger as saying, “If anyone sacrifices before the prayer, he is sacrificing only for himself; but if anyone sacrifices after the prayer, his rites are complete and he has correctly followed the practice of the Muslims."
Jundub b. ‘Abdallah al-Bajali reported God’s Messenger as saying, “If anyone sacrifices before the prayer, he must sacrifice another animal in place of it; but anyone who does not sacrifice till we have prayed must then sacrifice in God’s name."
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.