Heiser said that we need to understand the Hebrew mindset about the Law of Moses.
There are two types of law: serious moral concerns and mere ritual mistakes. Most of Leviticus is consumed in dealing with the latter. Rituals don’t have to be empty. I’ve written in the past that rituals teach us to take things seriously; it’s part of human nature. They are designed to answer the human need for a focal point in behavior. Also, the ritual law helps the Elect deal with all those who haven’t yet found themselves in feudal submission to the Lord.
A ritual mistake can be fixed; that’s what the sacrifices were meant to do. If you committed a serious moral error, there was no sacrifice for that. The latter was a major defilement of yourself, making you odious to God. Coming back from that was a whole different matter. A ritual mistake was a simple matter of following the prescribed rules to clean the slate. It was a matter of proper respect, a routine protocol.
Ritual uncleanness was communicable; moral sin was not. If you touch a woman in menstruation, you are ritually unclean. If you touch an adulteress, you don’t become ritually unclean. Ritual mistakes are a hassle; grave sins are a threat to everything, defiling the land and people. Grave sins may require capital punishment to keep peace with God.
What was a grave sin in the Old Testament is still a grave sin in the New. Ritual mistakes are generally not an issue in the New Covenant, though we do have equivalent rituals in Christ. We don’t require ritual offerings to restore balance; Christ took care of that part on the Cross. Gentiles can approach God in worship now.
I would add that it’s not as simple was calling the Ten Commandments “grave sins”. Paul made a major issue of things that are not listed in the Decalogue. You need to pay attention to the pattern of Jesus and His apostles to get a clue for what constitutes grave moral errors. You can repent and cleanse yourself from them, but it’s not a simple matter of ritual.
