Burnt offerings, grain offerings, peace offerings, sin offerings, guilt offerings, and the ordination offering; there were a lot of offerings and they all had to be done in a certain way.
Despite these offerings being ‘required’, they really were voluntary: there was no penalty if someone failed to bring a sin offering or guilt offering, other than separation from God. Those who wanted to please God (and be rid of their sin) brought offerings. Those who didn’t care probably didn’t bother, and they got to keep their sin with its eternal consequences.
When was a sin offering required? At this stage of Israel’s history, it was for refusing to testify against a crime, touching something or someone unclean, or making a foolish vow. A guilt offering was required for more tangible sins: defiling property, violating one of the Lord’s commands, or cheating, stealing or telling a lie. The guilt offering was demanding: a ram and silver for the tabernacle, and restitution (plus 20 per cent) to the victim.
We don’t need to make these offerings any more: Jesus fulfilled that part of the Law for us all. But the message stays the same: don’t sin against God or people.