You can't really understand Jesus to understand what He has completely fulfilled. You understand the general outline but the actual bullet points is beyond the doctrine most Reformed have no knowledge about. You have been taught it's not for today so you ignore it. However, Jesus said the one who teaches the LAW is the greatest in Heaven because it's not about works but about a former lifestyle for God's people that reflects how being a Christian is a current lifestyle that is different from the rest of humanity.
Jesus said the LAW won't end until Heaven and earth pass. That hasn't happened yet.
Indeed, the Law itself will not end until Heaven and earth pass. However, for those whom God had elected unto salvation - those whom God has placed under and will place under Christ - through Christ - and for them alone- the Law has ended; however, another Law exists and will continue to exist unto the end for the judgment of those not placed by God under the law of Christ.
The Law that should be taught is the law of Christ. That Law was fulfilled by Christ, and by fulfilling it, for His chosen, He satisfied all of the Law of the Law and the Prophets, and by so doing, has removed the requirement for them to do so. Therefore, by that, those laws can no longer be violated by them because they no longer exist for them. Those who do not teach the law of Christ, are teaching the violation of the law and prophets.
[Jhn 5:39 KJV]
39 Search the
scriptures; for
in them ye think ye have eternal life: and they are they which testify of me.
[Mat 5:17, 20 KJV]
17 Think not that I am come to destroy the law, or the prophets: I am not come to destroy,
but to fulfil. ...
20 For I say unto you,
That except your righteousness shall exceed [the righteousness] of the scribes and Pharisees, ye shall in no case enter into the kingdom of heaven.
[Rom 10:3-4 KJV]
3 For they being ignorant of God's righteousness, and going about
to establish their own righteousness, have not submitted themselves unto the righteousness of God.
4
For Christ [is] the end of the law for righteousness to every one that believeth.
[Rom 6:14 KJV]
14 For sin shall not have dominion over you:
for ye are not under the law, but under grace.
[Rom 8:2 KJV]
2
For the law of the Spirit of life in Christ Jesus hath made me free from the law of sin and death.
[1Co 15:56-57 KJV]
56 The sting of death [is] sin; and
the strength of sin [is] the law.
57
But thanks [be] to God, which giveth us the victory through our Lord Jesus Christ.
[Gal 3:10 KJV]
10
For as many as are of the works of the law are under the curse: for it is written, Cursed [is] every one that continueth not in all things which are written in the book of the law to do them.
[Gal 4:21-26 KJV]
21 Tell me,
ye that desire to be under the law, do ye not hear the law?
22 For it is written, that Abraham had two sons, the one by a bondmaid, the other by a freewoman.
23 But he [who was] of the bondwoman was born after the flesh; but he of the freewoman [was] by promise.
24 Which things are an allegory: for these are the
two covenants; the one from the mount Sinai, which gendereth to bondage, which is Agar.
25 For this Agar is mount Sinai in Arabia,
and answereth to Jerusalem which now is, and is in bondage with her children.
26
But Jerusalem which is above is free, which is the mother of us all.
[Gal 5:18 KJV]
18
But if ye be led of the Spirit, ye are not under the law.
[Phl 3:9 KJV]
9 And be
found in him, not having mine own righteousness, which is of the law, but that which is through the faith of Christ, the righteousness which is of God by faith:
[Heb 7:11 KJV]
11 If therefore
perfection were by the Levitical priesthood, (f
or 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 1:3 KJV]
3 Who being the brightness of [his] glory, and the express image of his person, and upholding all things by the word of his power,
when he had by himself purged our sins, sat down on the right hand of the Majesty on high;
[Heb 10:8-10, 12, 14 KJV]
8 Above when he said, Sacrifice and offering and burnt offerings and [offering] for sin thou wouldest not,
neither hadst pleasure [therein]; which are offered by the law;
9 Then said he, Lo, I come to do thy will, O God.
He taketh away the first, that he may establish the second.
10 By the which will
we are sanctified through the offering of the body of Jesus Christ once [for all]. ...
12 But this man,
after he had offered one sacrifice for sins for ever, sat down on the right hand of God; ...
14
For by one offering he hath perfected for ever them that are sanctified.