“For the priesthood being changed, of necessity there is also a change of the law” (Hebrews 7:12).
Many of the powerful arguments found in Hebrews are rooted in the proper use of inferencing. Examples include: a rest for God’s people not attained during the days of Joshua (3:7-4:10); the superiority of Melchizedek’s priesthood over the Levitical priesthood because of Abraham (7:1-10) and because of David’s prediction (7:11-28).
The proper use of inferencing when seeking to accurately understand the truth of God’s word is not ungodly or sinful. It is not optional, either.
Hebrews 7:12 is itself a statement of a necessary inference. Implicit in the prediction of a changed priesthood is a change of the law. This inference is necessary because the Law of Moses only authorized the tribe of Levi to officiate at the altar (Hebrews 7:13-14).
In addition, the phrase “a change of the law” implies that God—who had heretofore governed His chosen people via the Law of Moses—was going to govern His people via a different law. There would be a different standard or authoritative rule of conduct. The inspired New Testament writers use several different descriptors for this new covenant. These include: “the law of faith” (Romans 3:27), “the law of the Spirit of life” (Romans 8:2-3), “the law of God” (Romans 8:7), “the law of Christ” (Galatians 6:2), and “the perfect law of liberty” (James 1:25).
It is true that in the new covenant, we are not under the Law of Moses. It is not true that in the new covenant, we are not under law. God still has authoritative commands which must be obeyed and a code of conduct which must be adhered to.
There has been “a change of law”.