The Letter to the Hebrews finds theological significance, not only in the person of M as an individual, but also in his prieshood. This is why the phrase “the order of M” appears five times in the span of three chapters (Heb 5:6, 10: 6:20; 7:11, 17). The expression itself is taken from Psalm 110, where the Lord swears and oath of ordination to the Davidic Messiah, making the king at his right hand (Ps 110:1) a priest after the order of M (Ps 110:4).
The statement is striking, since for well over a thousand years, Israel knew only the Levitical priesthood of Aaron and his descendants established by the Mosaic covenant (Ex 40:12-15). No other priesthood was acknowledged by the Law or permitted to officiate on behalf of the covenant people (Num 17:1-13; 18:1-7).
So what is this “order” linked with M?
Genesis implies that the order of M is the patriarchal order of priesthood that function for many centuries before the ordination of Aaron and his sons took place at Mt. Sinai (Lev 8:1-36). In other words, it is the original, pre-Levitical form of the priesthood that was exercised during the long stretch of pre-Mosaic history. This was the age of natural religion, an era when priestly authority was rooted in the authority structure of the family.
In these ancient times, the father of the family conducted public rites of worship, and his sons became his successors in the ministry. In particular, the first-born son, by the natural right of primogeniture, was the primary heir who stood to receive the full measure of his father’s priestly and ruling responsibility. This is what we see throughout Genesis, where the Patriarchs- not a professional class of clerical priests- exercised spiritual leadership by:
building altars (Gen 12:7-8; 13:18), calling upon the Lord in prayer (Gen 21:33; 26:25), consecrating natural landmarks (Gen 28:18-22), pouring out libations (Gen 35:14), and offering sacrifice on behalf of the family (Gen 8:20; 46:1; Job 1:5).