“For when there is a change in the priesthood, there is necessarily a change in the law as well.”
This statement makes little sense if the priesthood is a result of the law but perfect sense if the law is a result of the priesthood. But, isn’t the priesthood described in the law? Yes, it is. But the description was created before it was put in the law. The priesthood came first in God’s scheme, and He gave the Law to Moses so that the people would understand the nature and purpose of the priesthood.
If God gave the law through Moses to outline the priesthood and all the various rules that governed the actual performance of that priesthood, then what would happen if God abandoned that priesthood? That is exactly what God did. He gave the priesthood through the law to serve the nation of Israel until such time as the Messiah would come and bring Jew and Gentile into a new Israel.
When God appointed a new high priest of a different tribe, then the law that designated that tribe had to be changed. Since the entire law was based on that Levitical priesthood, then the entire law had to be changed. A new covenant was made between God and His people through His son, governing the change in the priesthood.
Task for Today: Acknowledge the new covenant which replaces the old covenant (including the Ten Commandments). You do not need the covenant of Jesus and the Ten Commandments. Those ten rules went the way of the entire law. Celebrate the new covenant and the new priest. His priesthood is now the means of salvation. Today read of Him and obey Him.