Chapter I - Many Christians Are Confused About What our Relationship to the Old Testament And Its Laws Should Be.
Chapter II - What The New Testament Says About Old Testament Law
Chapter III - Jesus and The Spirit or Intention Behind The Law
ON THIS PAGE
Note: Unless otherwise stated all Biblical quotes are from the NASB
The Old and New Testaments each with their seemingly different teachings and commands has led to more than a little confusion
Ten Commandments Only?
If the Ten Commandments are the only Old Testament laws valid for today, we immediately run face first into two very large problems
Moral Laws Only?
Not so fast! Deciding which category (ceremonial, civil or moral) many of the laws fall into is not as easy as one might think
A Unified Whole
Unfortunately for us, James clearly informed us that anyone who breaks even one of the 613 laws is guilty of breaking them all
Who Exactly Was Under The Terms Of The Old Covenant And For How Long?
The Law, including the Ten Commandments and the Sabbath were given only to the "sons of Israel" (nation) of Israel, '"throughout Israel's generations"
The Old Testament's Place in Modern Christianity
Without the background and history of the Old Testament, we would know nothing about God, sin etc. In fact, the New Testament would make no sense whatsoever. Besides which, much that happened in ancient days serves as a warning and example for us.
The Bible - the only Word of God was written to provide a lamp to our feet and a light to our paths. It is our only sure guide to heaven, containing all the counsel and guidance we need to shepherd us along what is often a long and difficult journey. As Paul once wrote to his protégé...
All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness (2 Timothy 3:16).
However, a rather knotty problem arises in the fact that "all Scripture" includes both Old and New Testaments, each of which has seemingly different teachings and commands.
In Biblical times, the Law of Moses (also called Old Testament Law, Mosaic Law, or just The Law) regulated almost every aspect of Jewish life. The Ten Commandments and many other laws defined matters of morals, religious practice and government. It regulated the army, criminal justice, commerce, property rights, slavery, sexual relations, marriage and social interactions. It required circumcision for males, animal sacrifices, and strict Sabbath observance. It provided for the welfare of widows, orphans, the poor, foreigners and domestic animals. Ceremonial rules divided animals into "clean" and "unclean" categories. Clean animals could be eaten; unclean animals could not... Many of the laws were specific for the worship system and agricultural life of ancient Israel 
This has led to more than a little confusion for Christians who often struggle with the tension between the Old Testament emphasis on regulations, and the New Testament emphasis on grace. Because they have not grasped the seamless relationship between the two parts of the Scriptures, they are far from clear as to what our relationship to the Old Testament should be, especially when it comes to the many laws, including the keeping of the Sabbath and other Feasts of the Old Covenant. There are three points of view
1. Ten Commandments Only: Given the fact that the Ten Commandments are held in such high regard by most Christians and so often prominently displayed on the walls of public buildings, one has to suspect that most people (Christians and non-Christians alike) believe that the Ten Commandments are foundational laws that all Christians must conform to. In fact, many Christians will themselves tell you that the Ten Commandments are timeless moral laws which apply to all Christians for all time, while the rest of the OT law is not applicable to believers today.
2. Moral Laws Only: Other Christians make a distinction between ceremonial, civil and moral laws, the last category supposedly the only one that is still to be observed. In other words, our decision as to which laws we are to follow and which we can safely ignore is based solely on their content.
3. None of Them: Yet others are under the impression that because we are now under the New Covenant, none of the laws and regulations of the Old Testament apply to us.
Lets take a rational look at the first two viewpoints (the third is covered in Chapter III)
1)Ten Commandments Only?
If the Ten Commandments are the only Old Testament laws valid for today, we immediately run face first into two very large problems ...
a) Jesus identified the second greatest commandment as being "You Shall Love Your Neighbor As Yourself", which was a direct quote from the laws of Leviticus (19:18). If Jesus said an OT law, that was not included in the Ten Commandments, was the second greatest commandment ever, what basis do we have for arbitrarily rejecting all the regulations in the Pentateuch.
b) How many modern Christians do you know who obey the fourth Commandment?
'Observe the Sabbath day to keep it holy, as the Lord your God commanded you. 'Six days you shall labor and do all your work, but the seventh day is a Sabbath of the Lord your God; in it you shall not do any work, you or your son or your daughter or your male servant or your female servant or your ox or your donkey or any of your cattle or your sojourner who stays with you, so that your male servant and your female servant may rest as well as you. (Deuteronomy 5:12-14 NASB)
Note: One has to very much doubt that Moses would have accepted Sunday services as a substitute for keeping the Saturday Sabbath that was far more involved than simply going to church for an hour or two. The very term "Sabbath" derives from the Hebrew Shabbat which means "to cease". Starting at sundown on Friday until the appearance of three stars in the sky on Saturday night, the Sabbath severely limits what can be done on that day, but how many people cease from all work that is forbidden on Shabbat? In fact, the Sabbath was taken so seriously that, in the Book of Numbers (15:32-36), a man was executed for gathering wood on the Sabbath. (By the way, this is not a discussion as to why Sunday worship is appropriate).
And then there are some Christians who believe that the Sabbath's inclusion in the Ten Commandments means it is to be scrupulously observed.
But the question has to be asked... Why only the Sabbath?
There is absolutely nothing in Scripture to distinguish the Ten Commandments from the rest of the Old Testament laws, and the Sabbath from the other seven feasts (listed in Leviticus 23) that the Jews were beholden to keep. In fact, all seven were called "the feasts of the Lord" which means that they were instituted by the Lord Himself. They were "holy convocations" that took place at "appointed times". [See The Seven Feasts of Israel]
Yet, some of us believe we should keep the Sabbath, but are not obliged to keep these "holy convocations" I am afraid that the logic completely escapes me as it should anyone who has actually given the matter some thought.
And don't get me wrong If you wish to keep a version of the Sabbath and set aside a day of rest that is also devoted to the Father, you are more than welcome to do so. I am sure He will be quite pleased that you esteem Him so highly. What I dispute is that any Christian is obliged to keep the Sabbath .
2) Moral Laws Only?
There are those that believe that the content of the law is the criterion by which we decide which of the Mosaic laws are valid for today.
Many evangelical scholars interpret the Mosaic Law by emphasizing the distinction between moral, civil, and ceremonial laws. They define moral laws as those that deal with timeless truths regarding God's intention for human ethical behavior. "Love your neighbor as yourself" is a good example of a moral law. Civil laws are those that deal with Israel's legal system, including the issues of land, economics, and criminal justice. An example of a civil law is Deuteronomy 15:1, "At the end of every seven years you must cancel debts." Ceremonial laws deal with sacrifices, festivals, and priestly activities. An example is in Deuteronomy 16:13, which instructed the Israelites to "celebrate the Feast of Tabernacles for seven days after you have gathered the produce of your threshing floor and your winepress. 
In other words, we are to keep moral laws that are considered timeless, but can dispense with ceremonial and civil laws that were given thousands of years ago to a nation that belonged to a time and culture far removed from our own.
However, people who believe that only the so called "moral laws" are applicable to 21st century Christians face some insurmountable problems.
To begin with, it has to be noted that no such distinction occurs in Scripture, but has been imposed on the text. The Old Testament laws that we have so freely categorized are often found intermixed in the Old Testament. For example, the Ten Commandments are the clearest examples of "moral laws" yet, smack bang in the middle is one that is unmistakably and unarguably ceremonial - the Sabbath law or fourth commandment..
Besides which, the "moral law" of the Old Testament extend well beyond the Ten Commandments. In other places in the Old Testament we find commandments that order adulterers, fornicators, homosexuals and those who dishonor their parents to be put to death. For example..
'If there is anyone who curses his father or his mother, he shall surely be put to death; he has cursed his father or his mother, his blood guiltiness is upon him. 'If there is a man who commits adultery with another man's wife, one who commits adultery with his friend's wife, the adulterer and the adulteress shall surely be put to death. (Leviticus 20:9-10 NASB. See also 11-16).
So, what twisted logic dictates that we obey the moral laws of the Ten Commandments, but are allowed to ignore the moral laws in the rest of the Old Testament?
In any case,
Categorizing the Law is Nearly Impossible
Any one who gives the matter some thought will realize that deciding which category many of the laws fall into is not as easy as they may have thought.
Jesus identified Leviticus 19:18 ("You Shall Love Your Neighbor As Yourself") as the second greatest commandment ever. However this verse was directly followed by the commands to not breed together two kinds of your cattle, nor sow fields with two kinds of seed, nor wear clothing woven of two kinds of material" (19:19). Although there is absolutely nothing to suggest that any change has taken place, many have decided that verse 18 is a timeless moral law, therefore applicable to 21st century Christianity, but the very next verse is a civil law, and thus can be rejected. [Also See What is Holiness]
Not so fast!
While instructions on sowing your field may sound like a civil law, it really wasn't. As J. Daniel Hays so correctly pointed out....
"One of the central themes running throughout Leviticus is the holiness of God. The discourse by God in Leviticus 19 is prefaced by the commandment, "Be holy because I, the Lord your God, am holy." Part of this theme is the teaching that holy things must be kept separate from profane things. While the significance of these commands against mixing seed or mixing cloth material may not be fully understood, it is clear that they relate back to the holiness of God. In fact all of the levitical laws regarding separation seem to relate to the overarching principle of God's holiness and the separation required because of that holiness. How then can this law not be moral?" 
In other words, the distinctions between civil, ceremonial, and moral laws are far from clear. We make them based on a superficial reading of the text and without clear insight or understanding of the principal behind the law. In our usual fashion we, without giving the matter sufficient thought and study, pick and choose which of the Old Testament laws we will and will not obey based merely on whether a law seems to be relevant.
The fact of the matter is that the laws of the Old Covenant are...
A Unified Whole
In the words of Jason Dulle... (All Emphasis Added)
The Law of Moses was never fragmented into various parts, but was always viewed as one cohesive, unified whole. One had to keep all 613 commandments of the Law to receive of its benefits (Galatians 3:10-12). Moses said "cursed be he that confirmeth not all the words of this law to do them" (Deuteronomy 27:26) The Lord said through Jeremiah, "Cursed be the man that obeyeth not the words of this covenant, ...Obey my voice, and do them, according to all which I command you" (Jeremiah 11:3-4; See also Galatians 3:10). James summed it up best when he said, "For whosoever shall keep the whole law, and yet offend in one point, he is guilty of all" (James 2:10; See also v. 11). The Scripture declares that to keep 612 commandments, and yet fail to keep one, is to break all 613. To break a "ceremonial" law was viewed in the same manner as a "moral" law. Perfect obedience was demanded to all the commands of the covenant, because it was a unified whole.  Read Article
Note the use of the word "all" in Galatian 3:10 mentioned in the quote above. "For as many as are of the works of the Law are under a curse; for it is written, "cursed is everyone who does not abide by all things written in the book of the Law, to perform them." Which, if we are honest with our selves, doesn't find us in a very good position. James reinforced this when he so clearly informed us that anyone who breaks even one of the 613 laws is guilty of breaking them all.
In other words, if present-day Christendom is bound by the Ten Commandments, all Old Testament law should be obeyed, including the animal sacrifices, the seven feasts and the thrice yearly visits to Jerusalem. We can not pick and choose which of the Old Testament laws we will obey and which we will not.
All of which makes me wonder why it is that you can read a thousand articles on a thousand different websites or blogs about all the reasons that the author believes Jesus did not abolish the law, yet the author never ever claims to follow the whole law. I have wondered how many of these articles were written after a bacon breakfast!
The problem is keeping the Sabbath and the other festivals of the Old Covenant is not quite as simple as it sounds - in fact to keep them in the manner God ordained is completely impossible. In the words of pastor Tim Warner, (All Emphasis Added)
Lets get one thing straight right up front. Keeping the Feasts according to the Torah requires offering animal sacrifices. There is no avoiding this conclusion. And, any changes to the festivals by rabbis to accommodate the fact that there is no longer a Temple or Levitical priesthood, or, any changes by Messianic Christians to accommodate the fact that the New Testament says Christ's sacrifice has ended the animal sacrifices, makes it impossible to observe these feasts according to the Torah. What we are left with is a lot of man-made tradition as a substitute to what God commanded. Some of these traditions include things like substituting eggs for the Passover lamb on the Seder. How is this any different from people using "Easter eggs?"
Synagogue worship on Sabbath was never commanded by God. According to the Torah, all males must travel to Jerusalem 3 times a year to worship on the festival seasons. That was the worship God commanded in the Torah. No Jew or Messianic Christian on earth observes the feasts according to the Torah. And, there is a very good reason for this. The Temple was destroyed exactly 40 years [one generation] after Jesus began preaching, and the Levitical priesthood, which is necessary to observe the festivals, has been lost. So, how do Jews and Messianic Christians observe the feasts instead? Simply by following man's traditions, established by rabbis who flatly rejected Jesus as the Messiah. 
Sadly, modern Judaism takes the opinion of man more seriously than Torah. Since the temple was destroyed, and with it all the rituals that revolved around the building including animal sacrifices, the Rabbis (elevated to the status of prophet) decided that prayer ranks higher than sacrifices. They decided that "one who puts on phylacteries, recites the Shema, and offered prayer to God would be regarded as having sacrificed upon the great altar". [See Judaism And The Atonement] A typical example of man having the audacity to think he has the right and authority to change God's laws.
Remember that these laws were given to a very tiny nation, the sheer smallness of which made possible the physical keeping of some of the laws, i.e. they could travel to Jerusalem when needed, or when obliged to do so. Once Peter took the Gospel to the Gentiles many of the laws became very difficult to keep. In fact, as the Gospel spread to the furthermost corners of the earth and the number of Christians mushroomed, a huge number of the the Old Testament laws became completely unworkable.
The destruction of the Temple dealt the final blow to the physical keeping of the Law. One has to wonder why, if God intended the animal sacrifices to continue, He would let the Romans raze the Temple. However, even if it were still standing and in Jewish hands, how long do you think it would be before the sheer weight of numbers of Christians converging on Jerusalem three times a year, would make the Israeli authorities throw up their hands in horror and shut down the airports. Chaos doesn't even begin to describe the situation.
In other words, it is no longer possible to keep the law as the Father outlined. Luckily, it is not longer necessary to do so, simply because...
The Old Covenant (of Which The Law Was a Part) was Made With the Nation of Israel, Not Christians The World Over - It Was an Integral Part of The Narrative, Given At A Specific Point In Their History
Perhaps, so that we are all on the same page, we should first clarify exactly what a "covenant" is.
A covenant is a formal agreement between two parties - one stronger (the suzerain) and the other weaker (the vassal). Both the suzerain and the vassal receive a copy of the covenant that specifies what each party should receive from the other, and defines the penalties for failing to live up to the terms of the agreement.
In the Old Testament, the commandments given Israel through Moses at various times (Exodus 20 through Deuteronomy), were not presented as universal and timeless codes of behavior disconnected from the history of the nation. Much to the contrary, it was an integral part of the narrative of God delivering Israel from Egypt and, four decades later, leading them to the Promised Land. The law was a covenant between God and Israel and clearly defined what He would do for them - provided they kept their side of the agreement.
The book of Exodus relates how the Israelites were rescued from Egypt eventually arriving at Mount Sinai where they were first called into a covenantal relationship with the Almighty (chapter 19) and given the laws that began in chapter 20. However, as we all know, it didn't take them any time at all to break those laws, showing little trust in the Father. For this they were sentenced to live as nomads for 40 years until that faithless generation died off. Other laws set down in the books of Leviticus and Numbers were given at various points during their wandering through the desert with no fixed abode.
The legal material in the Book of Deuteronomy was given a new generation of Israelites just before they crossed the river Jordan and entered Canaan. They received a recapitulation of the covenant that the Father had made with their parents some forty years earlier. In Deuteronomy God specified exactly how they were to conduct themselves in the Promised Land, and what He would do or not do, based on whether or not they lived up to their end of the bargain..
In summary, the Law, including the Ten Commandments and the Sabbath were given only to the nation of Israel, as demonstrated by various verses scattered through the Old Testament. For example,
Then the Lord said to Moses, "Write down these words, for in accordance with these words I have made a covenant with you and with Israel." So he was there with the Lord forty days and forty nights; he did not eat bread or drink water. And he wrote on the tablets the words of the covenant, the Ten Commandments. (Exodus 34:27-28 NASB)
Now, O Israel, listen to the statutes and the judgments which I am teaching you to perform, so that you may live and go in and take possession of the land which the Lord, the God of your fathers, is giving you... "For what great nation is there that has a god so near to it as is the Lord our God whenever we call on Him? "Or what great nation is there that has statutes and judgments as righteous as this whole law which I am setting before you today? (Deuteronomy 4: 1, 7-8 NASB)
However, there is further supporting evidence.
There are two phrases that come up very frequently in the course of the instructions that the Lord gave the nation regarding the various laws and rituals that they were obliged to keep. These two phrases, that often occur in the same sentence, are a) "sons of Israel" that clearly shows who the laws were intended for. The second b) "throughout your (Israel's) generations" shows how long the laws were to stay in effect.
a) "Sons Of Israel"
is a term used well over 600 times in the Old Testament - over 350 times in the Pentateuch alone. So who exactly were the "sons of Israel"?
As we know, Jacob’s name was changed to "Israel" in Genesis 32:28. Later verses make it very obvious that Jacob's sons and grandsons - in fact all his descendants that made up the twelve tribes were known as the "sons of Israel"
In Genesis 46 the list of Jacob's sons and grandsons is introduced with the words "Now these are the names of the sons of Israel, Jacob and his sons, who went to Egypt". Referring to eleven of Jacob's sons (Joseph was already in Egypt) Genesis 42:5 says "So the sons of Israel came to buy grain among those who were coming, for the famine was in the land of Canaan also." Exodus 3:10 shows that even subsequent generations were known as Jacob's sons. This verse has the Lord telling Moses "Therefore, come now, and I will send you to Pharaoh, so that you may bring My people, the sons of Israel, out of Egypt." (NASB)
It was the "sons of Israel" - Jacobs descendants who were given the law.
Then the Lord spoke to Moses, saying, "Speak to the sons of Israel and say to them, 'When you enter the land which I am going to give to you and reap its harvest, then you shall bring in the sheaf of the first fruits of your harvest to the priest... 'Until this same day, until you have brought in the offering of your God, you shall eat neither bread nor roasted grain nor new growth. It is to be a perpetual statute throughout your generations in all your dwelling places. (Leviticus 23:9-10, 14 NASB)
Speak to the sons of Israel, saying, 'On the fifteenth of this seventh month is the Feast of Booths for seven days to the Lord... 'You shall thus celebrate it as a feast to the Lord for seven days in the year. It shall be a perpetual statute throughout your generations; you shall celebrate it in the seventh month'. (Leviticus 23:34, 41 NASB)
Now this is the law which Moses set before the sons of Israel; these are the testimonies and the statutes and the ordinances which Moses spoke to the sons of Israel, when they came out from Egypt, (Deuteronomy 4:44-45 NASB)
There was nothing in the ark except the two tablets of stone which Moses put there at Horeb, where the Lord made a covenant with the sons of Israel, when they came out of the land of Egypt. (1 Kings 8:9 NASB)
The Sabbath Was Also Given To The "Sons Of Israel"
"But as for you, speak to the sons of Israel, saying, 'You shall surely observe My Sabbaths; for this is a sign between Me and you throughout your generations, that you may know that I am the Lord who sanctifies you. (Exodus 31:13 NASB)
'So the sons of Israel shall observe the Sabbath, to celebrate the Sabbath throughout their generations as a perpetual covenant.' "It is a sign between Me and the sons of Israel forever; for in six days the Lord made heaven and earth, but on the seventh day He ceased from labor, and was refreshed." (Exodus 31:16-17 NASB)
Therefore, it makes absolute sense that after the Gospel was preached to the Gentiles and more and more of them became Christians, the Sabbath commandment was not repeated in the New Testament. In fact, the verse below makes it clear that the Sabbath is not applicable to New Testament Christians, at least not to those who are Gentiles. As it says, God delivered the Israelites from Egypt, therefore (or because of that) God commanded them to observe the Sabbath Day. Neither we, nor our ancestors, were slaves in Egypt rescued by God's mighty hand.
You shall remember that you were a slave in the land of Egypt, and the Lord your God brought you out of there by a mighty hand and by an outstretched arm; therefore the Lord your God commanded you to observe the Sabbath day. (Deuteronomy 5:15 NASB)
However, based on Exodus 31:16, there are many that claim that the Sabbath is still in effect. The verse reads 'So the sons of Israel shall observe the Sabbath, to celebrate the Sabbath throughout their generations as a perpetual (Heb. ôlâm) covenant.' See Footnote I
Also, for more information on Sabbath keeping see The Sabbath - Chapter Ten of Seventh Day Adventism
b) Through Israel's Generations
On several occasions God said that certain laws were in effect "throughout Israel's generations". In other words, numerous practices were to endure for the same length of time. The list is a very long one and includes,
Circumcision: God said further to Abraham, "Now as for you, you shall keep My covenant, you and your descendants after you throughout their generations. "This is My covenant, which you shall keep, between Me and you and your descendants after you: every male among you shall be circumcised. (Genesis 17:9-10 NASB. Also see verse 12)
The Weekly Saturday Sabbath: "But as for you, speak to the sons of Israel, saying, 'You shall surely observe My Sabbaths; for this is a sign between Me and you throughout your generations, that you may know that I am the Lord who sanctifies you. (Exodus 31:13 NASB)
Six of The Seven Feasts of Israel (Only Rosh HaShanah or the Feast of Trumpets: is not specifically mentioned as being 'throughout your generations').
The Passover: 'Now this day will be a memorial to you, and you shall celebrate it as a feast to the Lord; throughout your generations you are to celebrate it as a permanent ordinance. (Exodus 12:14 NASB)
First Fruits: Then the Lord spoke to Moses, saying, "Speak to the sons of Israel and say to them, 'When you enter the land which I am going to give to you and reap its harvest, then you shall bring in the sheaf of the first fruits of your harvest to the priest... 'Until this same day, until you have brought in the offering of your God, you shall eat neither bread nor roasted grain nor new growth. It is to be a perpetual statute throughout your generations in all your dwelling places. (Leviticus 23:9-10, 14 NASB)
Unleavened Bread: 'You shall also observe the Feast of Unleavened Bread, for on this very day I brought your hosts out of the land of Egypt; therefore you shall observe this day throughout your generations as a permanent ordinance. (Exodus 12:17 NASB)
The Feast of Weeks (Pentecost): 'On this same day you shall make a proclamation as well; you are to have a holy convocation. You shall do no laborious work. It is to be a perpetual statute in all your dwelling places throughout your generations. (Leviticus 23:21 NASB)
Yom Kippur or The Day of Atonement: Aaron shall make atonement on its horns once a year; he shall make atonement on it with the blood of the sin offering of atonement once a year throughout your generations. It is most holy to the Lord ." (Exodus 30:10 NASB. Also see Leviticus 23:30-31)
The Feast Of Tabernacles: "Speak to the sons of Israel, saying, 'On the fifteenth of this seventh month is the Feast of Booths for seven days to the Lord... 'You shall thus celebrate it as a feast to the Lord for seven days in the year. It shall be a perpetual statute throughout your generations; you shall celebrate it in the seventh month. (Leviticus 23:34, 41 NASB)
Misc: The Levites as Priests (Exodus 40:15 and Numbers 18:23), burning incense to the Lord (Exodus 30:8 NASB), sewing tassels on your clothes (Numbers 15:38 NASB), the blowing of the trumpets to convene an assembly (Numbers 10:8) etc. etc. etc.
The point here is that the Father expressly stated that all these practices were to continue for the same length of time - throughout Israel's generations. This means that if any of them have ceased - all of them will have done so. While the text does not specify exactly how many years, decades, or centuries that "Israel's generations" entails, it should be fairly obvious that when the Gospel came into effect, the dividing line between Jew and Gentile disappeared, marking the end of "Israel's generation".
Not only have numerous Old Testament regulations and customs faded, but some of them have actively been changed. A prime example is that under the covenant made at Mt. Sinai, only Aaron and his descendants could serve as priests,
"You shall thus give the Levites to Aaron and to his sons; they are wholly given to him from among the sons of Israel. "So you shall appoint Aaron and his sons that they may keep their priesthood, but the layman who comes near shall be put to death." (Numbers 3:9-10 NASB)
as a reminder to the sons of Israel that no layman who is not of the descendants of Aaron should come near to burn incense before the Lord; so that he will not become like Korah and his company--just as the Lord had spoken to him through Moses. (Numbers 16:40 NASB)
Yet, the book of Hebrews repeatedly tells us that Jesus is our eternal High priest.
Therefore, He had to be made like His brethren in all things, so that He might become a merciful and faithful high priest in things pertaining to God, to make propitiation for the sins of the people. (Hebrews 2:17 NASB)
For we do not have a high priest who cannot sympathize with our weaknesses, but One who has been tempted in all things as we are, yet without sin. (Hebrews 4:15 NASB)
So also Christ did not glorify Himself so as to become a high priest, but He who said to Him, "You Are My Son, Today I Have Begotten You"; just as He says also in another passage, "You are a priest forever according to the order of Melchizedek." (Hebrews 5:5-6 NASB)
Jesus was not a descendant of Aaron but came from the tribe of Judah. As Hebrews goes on to explain - the change in the priesthood meant a change in the Old Testament covenant and the law.
Now if perfection was through the Levitical priesthood (for on the basis of it the people received the Law), what further need was there for another priest to arise according to the order of Melchizedek, and not be designated according to the order of Aaron? (12) For when the priesthood is changed, of necessity there takes place a change of law also. (13) For the one concerning whom these things are spoken belongs to another tribe, from which no one has officiated at the altar. (14) For it is evident that our Lord was descended from Judah, a tribe with reference to which Moses spoke nothing concerning priests. (Hebrews 7:11-14 NASB)
The Old Testament's Place in Modern Christianity
However, if we are not beholden to the laws and regulations of the Old Testament, the question arises as to what place the older half of the Bible has in the lives of 21st century believers. After all Paul did say "All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness (2 Timothy 3:16)."
We need to consider that without the background and history of the Old Testament, the New Testament makes no sense whatsoever.
We would not know how sin came into the world and how sacrifice is necessary for forgiveness of sins. In fact, come to thing of it, we would know very little about the nature of God and His hatred of evil and virtually nothing about His coming kingdom. We would have absolutely no idea how the Israelites came to be God's chosen people - not only to preserve His words for the generations to come, but also to bring forth the Messiah Himself. The Old Testament also foretold literally dozens of details of His birth, life and death enabling us to properly identify Christ as God's sent one.
In fact, the Bible is an integrated whole to the extent that one section cannot stand with out the other; it is totally impossible to properly and completely understand the New Testament without the foundation on which it was built..
Although, the law code served its preparatory purpose and has passed away - superseded in authority by the New Testament, it remains inspired Scripture. This is what Paul said about the Old Testament record,
These things happened to them as examples and were written down as warnings for us, on whom the culmination of the ages has come
In other words, God hasn't changed, neither have His intents and purposes. His wrath against evil hasn't changed, and the fate of sinners and the rewards of the righteous remain the same. We need to pay attention to what lessons the OT teaches us, and be careful to avoid those situations that caused the wrath of God to fall on people's heads.
(1) For I do not want you to be unaware, brethren, that our fathers were all under the cloud and all passed through the sea; (2) and all were baptized into Moses in the cloud and in the sea; (3) and all ate the same spiritual food; (4) and all drank the same spiritual drink, for they were drinking from a spiritual rock which followed them; and the rock was Christ. (5) Nevertheless, with most of them God was not well-pleased; for they were laid low in the wilderness. (6) Now these things happened as examples for us, so that we would not crave evil things as they also craved. (7) Do not be idolaters, as some of them were; as it is written, "the people sat down to eat and drink, and stood up to play." (8) Nor let us act immorally, as some of them did, and twenty-three thousand fell in one day. (9) Nor let us try the Lord, as some of them did, and were destroyed by the serpents. (10) Nor grumble, as some of them did, and were destroyed by the destroyer. (11) Now these things happened to them as an example, and they were written for our instruction, upon whom the ends of the ages have come. (12) Therefore let him who thinks he stands take heed that he does not fall. (13) No temptation has overtaken you but such as is common to man; and God is faithful, who will not allow you to be tempted beyond what you are able, but with the temptation will provide the way of escape also, so that you will be able to endure it. (1 Corinthians 10:1-13 NASB )
Continue on to Chapter II - one of the primary themes of the New Testament is the superiority of the New Covenant, Paul going as far as to state that the law was a curse we have been redeemed from. HERE
A 'Perpetual' Covenant?
However, based on Exodus 31:16, there are many that claim that the Sabbath is still in effect. The verse reads 'So the sons of Israel shall observe the Sabbath, to celebrate the Sabbath throughout their generations as a perpetual (Heb. ôlâm) covenant.' (NASB)
The Hebrew word ôlâm, used over 400 times in the Old Testament, is defined by Strong's Lexicon as being "generally time out of mind (past or future), that is, (practically) eternity". Obviously why it is translated into the English everlasting, forever, perpetual etc.'
Abraham planted a tamarisk tree at Beersheba, and there he called on the name of the Lord, the Everlasting (Heb. ôlâm) God. (Genesis 21:33 NASB)
God, furthermore, said to Moses, "Thus you shall say to the sons of Israel, 'The Lord, the God of your fathers, the God of Abraham, the God of Isaac, and the God of Jacob, has sent me to you.' This is My name forever (Heb. ôlâm) , and this is My memorial-name to all generations. (Exodus 3:15 NASB)
Do you not know? Have you not heard? The everlasting (Heb. ôlâm) God, the Lord, the Creator of the ends of the earth does not become weary or tired. His understanding is inscrutable. (Isaiah 40:28 NASB)
However, there are verses where ôlâm cannot be understood quite as literally, but refers to a long, indefinite period. For example,
then his master shall bring him to God, then he shall bring him to the door or the doorpost. And his master shall pierce his ear with an awl; and he shall serve him permanently (Heb. ôlâm) . (Exodus 21:6 NASB)
Joshua said to all the people, "Thus says the Lord, the God of Israel, 'From ancient times (Heb. ôlâm) your fathers lived beyond the River, namely, Terah, the father of Abraham and the father of Nahor, and they served other gods. (Joshua 24:2 NASB)
But Hannah did not go up, for she said to her husband, "I will not go up until the child is weaned; then I will bring him, that he may appear before the Lord and stay there forever (Heb. ôlâm). (1 Samuel 1:22 NASB)
Behold, I am about to build a house for the name of the Lord my God, dedicating it to Him, to burn fragrant incense before Him and to set out the showbread continually, and to offer burnt offerings morning and evening, on Sabbaths and on new moons and on the appointed feasts of the Lord our God, this being required forever (Heb. ôlâm) in Israel. (2 Chronicles 2:4 NASB)
Additionally, if you believe the Sabbath is still binding today, you have to believe that the punishment for violating it is also in effect. Here is what the Lord said about those who failed to properly observe the Sabbath.
'For six days work may be done, but on the seventh day there is a Sabbath of complete rest, holy to the Lord; whoever does any work on the Sabbath day shall surely be put to death. (Exodus 31:15 NASB)
 The Christian Bible Reference Site. What Does the Bible Say About the Old Testament Law?
 J. Daniel Hays. Applying the Old Testament Law Today. http://www.biblicalstudies.org.uk/article_law_hays.html
 Jason Dulle. The Law: The Misunderstood Covenant. http://www.inplainsite.org/html/the_misunderstood_covenant.htm Pastor Tim Warner. Should Christians Celebrate the Jewish Feasts?