Why did God give Israel the ritual worship system and priesthood?
God gave Israel the ritual worship system and priesthood to compensate for their breaking of the moral law. This ecclesiastical part of the legal system, including the tabernacle and priesthood, instructed Israel exactly what to do under any set of circumstances.
Les explains that on top of the moral law, which Israel broke, God gave them the ritual or worship system—the ecclesiastical part of the legal system. This involved the tabernacle and the establishing of the priesthood, so that Israel would know exactly what to do under any set of circumstances. It was a compensatory system to address their breaking of the moral law.