Law is received through the priesthood. A change of priesthood requires a change of law. The new law is the spirit of life in Christ, and the law of faith.
If therefore perfection were by the Levitical priesthood, (for under it the people received the law,) what further need [was there] that another priest should rise after the order of Melchisedec, and not be called after the order of Aaron? For the priesthood being changed, there is made of necessity a change also of the law. Hebrews 7:11-12
A change of what Law?
Heb 7:11 If therefore perfection were by the Levitical priesthood, (for under it the people received the law,) what further need was there that another priest should rise after the order of Melchisedec, and not be called after the order of Aaron?
Heb 7:12 For the priesthood being changed, there is made of necessity a change also of the law.
OK, what Law is he speaking of here? This one...
Exo 28:1 And take thou unto thee Aaron thy brother, and his sons with him, from among the children of Israel, that he may minister unto me in the priest's office, even Aaron, Nadab and Abihu, Eleazar and Ithamar, Aaron's sons.
And did God mean what He said about the Priesthood being only for the sons of Aaron?
Num 16:1 Now Korah, the son of Izhar, the son of Kohath, the son of Levi, and Dathan and Abiram, the sons of Eliab, and On, the son of Peleth, sons of Reuben, took men:
Num 16:2 And they rose up before Moses, with certain of the children of Israel, two hundred and fifty princes of the assembly, famous in the congregation, men of renown:
Num 16:3 And they gathered themselves together against Moses and against Aaron, and said unto them, Ye take too much upon you, seeing all the congregation are holy, every one of them, and the LORD is among them: wherefore then lift ye up yourselves above the congregation of the LORD?
Korah, Dathan and Abiram seemed to think they had just as much right to the Priesthood. What did God say?
Num 16:8 And Moses said unto Korah, Hear, I pray you, ye sons of Levi:
Num 16:9 Seemeth it but a small thing unto you, that the God of Israel hath separated you from the congregation of Israel, to bring you near to himself to do the service of the tabernacle of the LORD, and to stand before the congregation to minister unto them?
Num 16:10 And he hath brought thee near to him, and all thy brethren the sons of Levi with thee:
and seek ye the priesthood also?
Num 16:11 For which cause both thou and all thy company are gathered together against the LORD: and what is Aaron, that ye murmur against him?
Num 16:16 And Moses said unto Korah, Be thou and all thy company before the LORD, thou, and they, and Aaron, to morrow:
Num 16:17 And take every man his censer, and put incense in them, and bring ye before the LORD every man his censer, two hundred and fifty censers; thou also, and Aaron, each of you his censer.
Num 16:18 And they took every man his censer, and put fire in them, and laid incense thereon, and stood in the door of the tabernacle of the congregation with Moses and Aaron.
Num 16:19 And Korah gathered all the congregation against them unto the door of the tabernacle of the congregation: and the glory of the LORD appeared unto all the congregation.
Num 16:20 And the LORD spake unto Moses and unto Aaron, saying,
Num 16:21 Separate yourselves from among this congregation, that I may consume them in a moment.
To say that God was displeased was putting it mildly.
Num 16:23 And the LORD spake unto Moses, saying,
Num 16:24 Speak unto the congregation, saying, Get you up from about the tabernacle of Korah, Dathan, and Abiram.
Num 16:25 And Moses rose up and went unto Dathan and Abiram; and the elders of Israel followed him.
Num 16:26 And he spake unto the congregation, saying, Depart, I pray you, from the tents of these wicked men, and touch nothing of theirs, lest ye be consumed in all their sins.
Num 16:27 So they gat up from the tabernacle of Korah, Dathan, and Abiram, on every side: and Dathan and Abiram came out, and stood in the door of their tents, and their wives, and their sons, and their little children.
Num 16:28 And Moses said, Hereby ye shall know that the LORD hath sent me to do all these works; for I have not done them of mine own mind.
Num 16:29 If these men die the common death of all men, or if they be visited after the visitation of all men; then the LORD hath not sent me.
Num 16:30 But if the LORD make a new thing, and the earth open her mouth, and swallow them up, with all that appertain unto them, and they go down quick into the pit; then ye shall understand that these men have provoked the LORD.
Num 16:31 And it came to pass, as he had made an end of speaking all these words, that the ground clave asunder that was under them:
Num 16:32 And the earth opened her mouth, and swallowed them up, and their houses, and all the men that appertained unto Korah, and all their goods.
Num 16:33 They, and all that appertained to them, went down alive into the pit, and the earth closed upon them: and they perished from among the congregation.
Hmmm, their attempt to do the Priestly duties didn't last long did it? Why? They were Levites but they were not the sons of Aaron. The Priesthood was reserved for the sons of Aaron only.
Heb 7:13 For he of whom these things are spoken pertaineth
to another tribe, of which no man gave attendance at the altar.
Heb 7:14 For it is evident that our
Lord sprang out of Juda; of which tribe Moses spake nothing concerning priesthood.
Now which of the Ten Commandments specifies that the Priesthood is of the tribe of Levi and the sons of Aaron? If you said none, very good, if not go back and reread Ex 20. Now back to Hebrews...
Heb 7:15 And it is yet far more evident: for that after the similitude of Melchisedec there ariseth another priest,
Heb 7:16 Who is made, not after the law of a carnal commandment, but after the power of an endless life.
Heb 7:17 For he testifieth, Thou art a priest for ever after the order of Melchisedec.
Heb 7:18 For there is verily a disannulling of the commandment going before for the weakness and unprofitableness thereof.
Which commandment?
Exo 28:1 And take thou unto thee Aaron thy brother, and his sons with him, from among the children of Israel, that he may minister unto me in the priest's office, even Aaron, Nadab and Abihu, Eleazar and Ithamar, Aaron's sons.
Heb 8:1 Now of the things which we have spoken this is the sum: We have such an high priest, who is set on the right hand of the throne of the Majesty in the heavens;
Heb 8:2 A minister of the sanctuary, and of the true tabernacle, which the Lord pitched, and not man.
Heb 8:3 For every high priest is ordained to offer gifts and sacrifices: wherefore it is of necessity that this man have somewhat also to offer.
Heb 8:4
For if he were on earth, he should not be a priest, seeing that there are priests that offer gifts according to the law:
Again, which Law? Ex 28:1 According to that Law Christ could not be a Priest. Now Christ is the God of the Old Testament, He was I AM and He woudl not violate His own Law so the Law concerning the Priesthood had to be changed. Teh Law concerning the Priesthood was part of the Law of Moses, the Ten Commandments are God's Law and are not changeable.