Zaid b. Arqam said the companions of God’s Messenger asked him the significance of these sacrifices and he replied, “It is a custom which has come down from your father Abraham." They asked what reward they would receive for them and he replied, “For every hair you will receive a blessing." They asked about wool, and he replied, “For every strand of wool you will receive a blessing."
I was present at the festival on the day of sacrifice along with God’s Messenger. He had done no more than finish his prayer and give the salutation when he saw the flesh of sacrificial animals which had been sacrificed before he finished his prayer. So he said, “Anyone who has sacrificed before he prayed (or, we prayed) must sacrifice another in place of it." In a version he said: The Prophet prayed on the day of sacrifice, then delivered a sermon, then sacrificed, and he said, “Anyone who has sacrificed before he prayed (or, we prayed) must sacrifice another in place of it, and if anyone has not sacrificed he should do so in God’s name."