The author of the letter to the Hebrews makes a comparison between two priestly orders – the Levitical order of priests under the Sinai Covenant and its Laws, and the order of Melchizedek. He does this because Jesus is the high priest of those brought forth by God, a high priest corresponding to the order or arrangement of Melchizedek.
He says, ‘….if the people were completely fulfilled and made complete through the Levitical priesthood – on the basis that it was ordained and sanctioned by Covenant Law – why is there still need for another priest to be raised up according to the rank of Melchizedek, not being spoken of according to the rank of Aaron? [A Levite] 12 Because the priesthood is being transferred from out of necessity, from out of compelling need, and a transfer of law is coming into being. 13 Because these things [about Jesus as high priest] are being said on the basis of another tribe participating, away from which no one held towards the altar. 14 Because it is very clear that our Lord rises from out of Judah, penetrating into which tribe Moses says nothing around priests. 15 And it is even more abundantly clear if another priest is arising down from a resemblance to Melchizedek, 16 who is not caused to come into being down from a fleshly command of law, but down from power and ability of indissoluble life. 17 Because it is testified: ‘You are a priest penetrating into the age, down from the arranged order of Melchizedek’, [Psalm 110 v 4], (Hebrews 7 v 11 – 17).
The first key thought for us here is that there is a transference of priesthood. Jews who become Christians are placed into a new and different priesthood with Jesus as the high priest. On becoming Christians they are no longer under the Levitical priesthood but have become members of a new priesthood that resembles that of Melchizedek at the time of Abraham. By comparison, Gentiles who are not Christians are not under the Levitical order of priests. But on being brought forth by God through the Messiah, they too are placed as members of this priesthood that corresponds to that of Melchizedek.
Jesus comes from the Hebrew tribe of Judah, yet Moses, in mediating the Sinai Covenant and its Laws, says nothing about priests from Judah attending to the altar and its sacrificial duties. Jesus does not arise as high priest from out of a fleshly command of divine Law (verse 16) but from power and ability of an indissoluble life. The phrase ‘a fleshly command of Law’ may at first seem difficult to understand, but in this context it seems to mean the requirement or injunction of ‘the divine Law that states that in order to qualify be a priest a Jew had to be a physical descendant of Levi’ – a Levite.