Enter the Jews
When Abraham and his clan came along on the scene, the sacrificial system was a part of life. Altars for sacrifice were built at all key parts of their personal history.
An important episode in Abraham's life involved a very important sacrifice. God told him to take his son, Isaac, to the region of Moriah and, once there, to offer Isaac as a burnt sacrifice. Was this to be a new development in man's relationship with God, child sacrifice? Certainly not! In God's eyes, child sacrifice was an abomination. No, this was to be a test of Abraham's faith, a test that he passed with flying colours and would forever label him as the 'father of faith'.
By the time of Moses, a few hundred years later, a whole complex sacrificial system had been developed. It wasn't a case of offering the first-born lamb and hoping for God's pleasure. Now there were at least five types of sacrifice. The burnt offering tended to be used as atonement for unintentional sin, the grain offering for recognition of God's goodness, the fellowship offering for thanksgiving and fellowship, the sin offering was for the general forgiveness of sin and the guilt offering was for sin that required restitution.