The Greek verb translated into 'abolish, annul, demolish' in Matthew 5:17 means 'to loose'. That means Jesus did not come to lift restrictions or impose restrictions in the Jewish Bible which Christians refer to as the Old Testament. When Jesus and only Jesus abolishes the few things necessitated by His death, He uses the clear phrase "You have heard that...But I say to you" to signify the change. If we do not read that phraseology in any of the laws which men teach have shifted in the New Testament, we are in the realm of Satan.
In applying Judaism in the Christian daily life, even though Jesus has trumpeted that His coming does not loose the Law or the Prophets, yet, the disguised messengers of light associate Jesus with their antichrist false doctrines to not keep the Shabbat, for example, because of the Cross. Yet, on Sinai, God (Jesus) says that the Shabbat has to be kept because He rested on it after the Creation works, that is, before the appearance of sin. In other words, the Shabbat day has nothing to do with the plan of Redemption. The Shabbat day is not the Lamb which is not killed any more.
Jesus is the Lamb, our Passover, not the fulfillment of the Shabbat day. Besides, Jesus claims ownership of the Shabbat day. As such, how can He own something when He was alive on earth and lose it after He was risen? Where do we read that He traded His Special Day for the first of the 6 days that He gave to men? Where do we find a declaration of that trade?
Matthew 5:38-39 EMTV (38) "You have heard that it was said, 'An eye for an eye and a tooth for a tooth.' (39) But I say to you not to resist an evil person. But whoever shall slap you on your right cheek, turn to him the other also.
If we understand the parable of Lazarus and the rich man, those who want to be saved cannot follow any teaching of men that counters what is written in the Law or the Prophets. In the parable, we learn that the Law and the Prophets exist to keep us from going to the hell to come. We also learn that there is no special revelation on the will of God by Jesus when we disagree with the Law or the Prophets, even if we have a personal relationship with Jesus. Because, according to the parable, if we do not obey Moses and the Prophets, we will not listen to anyone from Heaven or someone who would come from Hell.
Luke 16:27-31 Darby
(27) And he said, I beseech thee then, father, that thou wouldest send him to the house of my father,
(28) for I have five brothers, so that he may earnestly testify to them, that they also may not come to this place of torment.
(29) But Abraham says to him, They have Moses and the prophets: let them hear them.
(30) But he said, Nay, father Abraham, but if one from the dead should go to them, they will repent.
(31) And he said to him, If they hear not Moses and the prophets, not even if one rise from among the dead will they be persuaded.
The Key Principle to fend off false doctrines: No iota in Moses can change (Matthew 5:18); only the rites and their associated rituals and their sabbaths are no more.
If nothing can change in the Old Testament, the Sabbath to remember cannot be forgotten, the restrictions in food cannot be lifted, et cetera.
For amein I say unto you, Till heaven and earth pass, one yod or one tittle shall in no wise pass from the Torah, till all be fulfilled. Matthew 5:18 Cepher