Hello Leaf,
Of course the law in regards to the Priesthood has been changed. Jesus was of the tribe of Judah where as only those from the tribe of Levi were allowed to be Priests under the old covenant earthly Sanctuary system *Numbers 18:1-5. According to the scriptures in Hebrews 7:1-25 there needed to be a change in the law so that Jesus coming from the tribe of Judah could take on the role of High Priest to minister in the Heavenly Sanctuary that the Lord pitched and not man based on better promises *Hebrews 8:1-6.
Change of the law of the Priesthood...
Hebrews 7:11-19, [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? [12],
For the priesthood being changed, there is made of necessity a change also of the law. [13], For he of whom these things are spoken pertains to another tribe, of which no man gave attendance at the altar. [14],
For it is evident that our Lord sprang out of Juda; of which tribe Moses spoke nothing concerning priesthood. [15], And it is yet far more evident: for that after the similitude of Melchisedec there rises another priest, [16], Who is made, not after the law of a carnal commandment, but after the power of an endless life. [17], For he testifies,
You are a priest for ever after the order of Melchisedec. [18],
For there is truly a cancellation of the commandment going before for the weakness and unprofitableness thereof. [19], For the law made nothing perfect, but the bringing in of a better hope did; by the which we draw near to God.
As shown above the change of the law here was the change of the laws concerning the Priesthood not the 10 commandments.
As to your question these laws here as posted earlier in regards to the "
shadow laws" for the remission of sins (Levitical Priesthood, earthly Sanctuary, animal sacrifices and sin offerings and other offerings etc) were all "
shadow laws" pointing to the body of Christ *Colossians 2:17 and are fulfilled in Christ and are now continued in Christ based on better promises *Hebrews 8:1-6.
They are not abolished but continued in Christ under Gods new covenant promises. These "shadow laws" however are not Gods' eternal laws that do not change and are the standard of what sin is when broken and righteousness when obeyed in Gods' 10 commandments. of course Gods' 4th commandment Sabbath is one of God's 10 commandments according to Exodus 20:8-11 and one of Gods' 10 commandments that give us the knowledge of what sin is when broken and righteousness when obeyed (Romans 3:20; Romans 7:7; 1 John 3;4; James 2:10-11; Psalms 119:172; 1 John 3:6-9; 1 John 2:3-4)
There is two parts to Matthew 5:17-28.
1. The fulfillment of the shadow laws the point to Jesus as the coming Messiah and Gods' plan of salvation for all mankind in the new covenant promise of Hebrews 8:10-12 from Jeremiah 31:31-34 and Ezekiel 36:24-27
The first part is in reference to Jesus fulfilling the Mosiac "shadow laws" of the old covenant that all pointed to Jesus as the coming Messiah and Gods' plan of salvation for all mankind under the new covenant (Levitical Priesthood, animal sacrifices and sin offerings, earthly Sanctuary and its laws, circumcision, Feast days). All of these laws are fulfilled in Jesus and continued in Him based on better promises (Hebrews 7:1-25; Hebrews 8:1-13; Hebrews 9:1-28; Hebrews 10:1-22)
2. The redemption of all mankind from sin through faith in Gods' Word.
Jesus came to magnify the law from the inside out quoting
Matthew 5:17-32 (thoughts and feelings) in fulfillment of *
Isaiah 42:21. This is to show that unless our righteousness exceeds the righteousness of the Scribes and Pharisees we can in no way enter into the kingdom of heaven. Jesus is saying the problem runs deeper then outward observance to the 10 commandments. Evil begins in the heart. Breaking anyone of God's 10 commandments from the heart defile a man according to Jesus in *
Matthew 15:18-19.
Jesus is saying we can be outwardly perfect and blameless like the Scribes and Pharisee but inwardly like dead mans bones in *
Matthew 23:27-28. Jesus is magnifying the God’s 10 commandments in Matthew 5 from the inside out to our very thoughts and feelings. To show us that we are all sinners in need of a Saviour and that sin originates in the heart (thoughts and feelings) which is why we need a new one *Ezekiel 36:24-27.
That is why we have the new covenant promise to of God’s salvation from sin and a new heart to love which is why we need to be born again by faith in God's Word *1 John 5:4 for God’s salvation is to free us from the power of sin (breaking any one of God's 10 commandments) *Romans 8:1-4; Romans 6:1-23; Romans 3:31; John 8:31-36;
Hebrews 8:10-12;
1 John 3:3-10.
..................
There are two parts to Matthew 5. The first is Jesus fulfilling the law and the prophets as the promised Messiah and the second is in regards to our salvation from sin through the power of God by faith in Gods' Word to be born again into Gods' new covenant promise to all those who believe. None of the laws and the prophets are abolished according to Jesus that are fulfilled in him and also in us as we believe and follow His Word....
Romans 8:1-4 [1], There is therefore now no condemnation to them which are in Christ Jesus, who walk not after the flesh, but after the Spirit. [2], For the law of the Spirit of life in Christ Jesus has made me free from the law of sin and death. [3], For what the law could not do, in that it was weak through the flesh, God sending his own Son in the likeness of sinful flesh, and for sin, condemned sin in the flesh: [4],
That the righteousness of the law might be fulfilled in us, who walk not after the flesh, but after the Spirit.
God's new covenant promise to to fulfill His law in our hearts as we are born again through faith *Hebrews 8:10-12; from Jeremiah 31:31-34; Ezekiel 36:24-27 (see also Romans 13:8-10; James 2:8-12; John 14:15; John 15:10 and 1 John 5:2-4 ). Faith however does not abolish God's law (10 commandments) it establishes Gods' law in all those who have faith... Romans 3:31 Do we then make void the law through faith?
God forbid: yes, we establish the law.
Hope this is helpful.