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Fulfilling the Law; The Impossible Mission: Matthew 5:17-20

I am a Christian pastor who wishes to bring glory to God in all that I do, and to help people through my writing to know Him better.


Introduction: Law Points Out Sin

I am continually amazed by how far away the average Christian has strayed from biblical knowledge and how they are adopting more and more of a secular world-view. For instance, the American Worldview Inventory 2020 Survey, conducted by the Cultural Research Center at Arizona Christian University, found that a majority of people who describe themselves as Christian (52%) accept a “works-oriented” means to God’s acceptance.

They found that less than half, only 42% expect to experience salvation as a result of their confession of sin and acceptance of Jesus Christ as Savior. Huge proportions of people who come from churches whose doctrine teaches that you can only be saved and get into heaven by accepting Jesus Christ as your Savior rather believe that you can make it by doing or being good. That includes 44% of people in mainline protestant churches and 41% in what are considered evangelical churches.

Let me say this loud and clear. The Bible teaches that salvation is by grace alone through faith alone in Jesus Christ alone. If you are expecting to get into heaven on your own merits, by your own works, you will fail! Good works never have and never will save anyone.

Further, the Law of Moses, while being good, will never bring salvation. It was not intended to do that. Rather, it was given to the people of Israel, who were already in a covenant relationship with God. They were His chosen people, saved out of the land of Egypt and were in the process of being lead into the promised land when they received the Law on Mount Sinai.

We are studying the Sermon on the Mount, which is arguably the most famous sermon in the world. In it Jesus is giving His vision for the future which He called the Kingdom of God. The Lord, in the sermon, places a high emphasis on 'purity of heart' and it embodies the basic standards of being a Christian.

This discourse is a masterful exposition of the Law and an assault on pharisaic legalism. Jesus expounds the full meaning of the law and by this shows that its demands were humanly impossible. As John MacArthur tells us:

"It closes off every possible avenue of human merit and leaves sinners dependent on nothing but divine grace for salvation."

In Matthew 5:17-20 Jesus talks about the Mosaic law specifically and shows us His relationship with it and how His mission to earth affected the law. He also begins to show why it would have been impossible for anyone who heard His message to be saved by attempting obedience to the law of Moses.

Let us examine these 4 verses and see how Jesus' message to His disciples in His day affects us who are living in the 21st century as members of the Body of Christ. But first allow me to give a short biblical overview of why the Law of Moses was given in the first place.

I. The Purposes of the Law

If we look throughout Scripture, we can get a picture as to what was the Law's purposes. To be clear, in referring to the Law in Scripture, it is talking about those set of rules and regulations which God gave to Moses on Mount Sinai. They include the Ten Commandments, ordinances for living in society, and regulations for worship ( i.e. requirements for priests, sacrifices, feasts, and the temple).

We can see at least 4 purposes for the Law. The first was for the good of God's people Israel. We can see this fact in Deuteronomy 10:12,13 where it says:

"And now, Israel, what does the LORD thy God require of you, but to fear the LORD your God, to walk in all his ways, and to love him, and to serve the LORD your God with all your heart and with all your soul, To keep the commandments of the LORD, and his statutes, which I command you this day for your good?"

The Lord didn't want His people doing the things that the other nations were doing because He knew that they would be destroyed by following them. He wanted the Mosaic Law to be a blessing to His people. That is easily seen in commands like "Do not murder", "Do not lie" and Do not steal." Any society which follows such commands will be a better and more safe place in which to live.

We can see how much God loved His people by giving them the Law in passages such as Deuteronomy 5:29,33. He says this:

"Oh that they had such a heart as this always, to fear me and to keep all my commandments, that it might go well with them and with their descendants forever!" "You shall walk in all the way that the LORD your God has commanded you, that you may live, and that it may go well with you, and that you may live long in the land that you shall possess."

The next reason that we can glean for the Mosaic Law is that it was given to show God's people Israel that He is a holy God and was to be feared.

We can find in such passages as Leviticus 19:2 that God tells His people to be holy because He is holy. The term literally means separate or 'set apart.' By saying that God is Holy, Scripture is saying that He is set apart and separate from all others. There is none like Him However, it also means there is no trace of evil in his character. In one sense only God is truly holy. For only He is totally flawless in His character.

Also, the holy God hates sin and all that goes against His perfect will. And anyone who truly loves the Lord should not want to sin against Him. The Lord should be reverenced and respected by those who claim to follow Him, by their obedience:

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We see this plainly in Deuteronomy 31:12,13 where it states:

"Gather the people together, men and women and little ones, and the stranger who is within your gates, that they may hear and that they may learn to fear the Lord your God and carefully observe all the words of this law, and that their children, who have not known it, may hear and learn to fear the Lord your God as long as you live in the land which you cross the Jordan to possess.”

A third reason for the Mosaic law was to set Israel apart as different from other nations. We find this in passages such as Deuteronomy 28:1,9-10 where it says:

"And if you faithfully obey the voice of the LORD your God, being careful to do all his commandments that I command you today, the LORD your God will set you high above all the nations of the earth. … The LORD will establish you as a people holy to himself, as he has sworn to you, if you keep the commandments of the LORD your God and walk in his ways. And all the peoples of the earth shall see that you are called by the name of the LORD, and they shall be afraid of you."

A fourth and final reason for the Law that Moses received was probably the most important of all. It was given to point out the need of the world for a Savior. Paul said in Romans 3:19 that it was given so:

"that every mouth may be stopped and that all the world may become guilty before God."

He also said:

“Therefore by the deeds of the law there shall no flesh be justified in his sight: for by the law is the knowledge of sin.” (Romans 3:20).

On top of that the great apostle tells us that:

"Wherefore the law was our schoolmaster to bring us unto Christ, that we might be justified by faith." (Galatians 3:24).

Once again, the law never saved anyone. Rather, it showed everyone their need for a Savior.

It is with these things in mind that we now turn to Jesus' words in HIs sermon regarding the law of Moses.

II. Jesus Came to Fulfill the Law (19)

Jesus begins his talk about the law by saying something very important. He tells His listeners that:

"Do not think that I came to abolish the Law or the Prophets; I did not come to abolish but to fulfill." (17).

The Lord was not anti-law. He recognized that it was good and He understood its true meaning and significance. Further, by saying both the Law and the Prophets Jesus is referring to all of the Old Testament Scriptures.

The Old Testament points to Jesus who was to come. The word 'fulfill' speaks of fulfillment in the same sense that prophecy is fulfilled. Jesus fulfilled all the law in every one of its aspects. He fulfilled the moral law by keeping it perfectly. He fulfilled the ceremonial law, with all of its sacrifices and offerings, by being the very embodiment of everything the types and symbols pointed to. And finally, He fulfilled the judicial law by personifying God's perfect justice.

Our Lord pays respect to the Law even more fully by saying in verse 18 that:

"For truly I say to you, until heaven and earth pass away, not the smallest letter or stroke shall pass from the law until all is accomplished."

Christ here is affirming the inerrancy and absolute authority of the Old Testament Scriptures. He used a description of the law's accomplishment that is quite interesting here by talking about the smallest letter or stroke not passing away. The King James uses the words jot and tittle. The phrase means a very small amount.

A jot is the tenth letter in the Hebrew alphabet and the smallest. It was written above the line and looks to us rather like an apostrophe. Jot is related to our modern English word iota, meaning “a very small amount.” The Hebrew word is spelled yod or yodh.

A tittle is even smaller than a jot. A tittle is a letter extension, a pen stroke that can differentiate one Hebrew letter from another.

In other Words, the New Testament didn't do away with the Old Testament but brought it to completion and explains it. For example, the sacrifices and offerings, or the requirements of the ceremonial law, were fulfilled in Jesus Christ. That is why we no longer have to do them. He accomplished them for all time.

So we must never look down on the Law given to Moses as something inferior that needed to be replaced. It was rather a demonstration of God's righteousness that foreshadowed better things to come. And those thing are found in Jesus Christ.

III. The Consequences of Teaching or Practicing Disobedience to the Law (19)

Jesus then goes on to reprimand those who would practice disobedience to the commandments or teach disobedience to any of them. This is found in verse 19. At first glance it appears He is also referring to the ceremonial Law as part of that which is binding to his disciples. However, the usage of the word 'commandments' here is almost exclusively confined to the moral laws at the time that Jesus used it. In other Words, the Ten Commandments.

Jesus said there would be consequences to annulling or setting aside even the least of God's commandments and teaching others to do so as well. Those who did so would be ranked least in the Kingdom of Heaven. However, those who would keep them and teach others to do the same would be called great in the Kingdom.

Notice that even in this Kingdom Dispensation where Jesus is talking to Israel, who were given these commandments, He is not referring to salvation by keeping the Law, or losing your salvation by not keeping it. He is talking about rewards for the disciples that follow the good commandments which God had given His people.

To earn salvation by the Mosaic law, one would have to keep it perfectly. And no person, apart from the God-man Jesus Christ, would ever be able to do such a thing. Further, if one doesn't believe this, Jesus goes on to show how hard it would be to enter God's Kingdom by the works of the Law, beginning in verse 20.

IV. The Impossibility of Salvation by the Law (20)

In this verse, Jesus begins to do what He will continue to do throughout the Sermon on the Mount. He shows that keeping the Law perfectly is so exacting as to be out of reach to anyone. He states:

"For I say to you that unless your righteousness surpasses that of the Scribes and Pharisees, you will not enter the kingdom of Heaven."

A Scribe was part of a group whose profession was writing. They were experts in the Law and could draft legal documents (contracts for marriage, divorce, loans, inheritance, mortgages, the sale of land, and the like). They were involved in many administrative tasks and also interpreted the law.

The Jewish people had no official ruling class after their return from exile, so they turned to religion and turned its commandments into laws and regulations. This means that the work of the scribes also had judicial value.

The Pharisees were the religious fundamentalists of the day. They were a powerful religious political group who also interpreted the Jewish Law. Their name means "separate ones." Here is how one unknown author describes them:

"From the synagogue, they studied, focused on the schooling of children and did missionary work to spread the word of God. Only people from old Pharisee families could become part of this priestly elite. Old Pharisee families could be traced back to the people who fought to free Palestine from Greek occupation.

Their main concern was that of getting the Jewish people to follow the word of God in all aspects of their lives. They imposed all laws, whether regarding spiritual life or normal, mundane things. According to Halley's Bible Handbook:

"Pharisees were the most numerous and influential of the religious sects of Jesus' day. They were strict legalists. They stood for the rigid observance of the letter and forms of the Law, and also for the Traditions."

Their problem was that their primary focus was on external obedience and not on the heart. They looked good on the outside but Jesus called them 'white-washed sepulchres whose insides contained dead men's bones. (Matthew 23:27).

A sepulchre is basically a stone room with a stone coffin where a dead body lies. The word comes from the Latin sepulcrum, which means “burial place,” Contact with a sepulchre brought with it ceremonial uncleanness, and all burial-places were accordingly white-washed once a year to warn passers-by not to come near.

Further, like the white-washed sepulchres, the Pharisees may have seemed to look good. However, internally they were full of sin, death and decay.

So, in order to enter the Kingdom of Heaven, you couldn't just have the outer display of knowledge and works. The Scribes, and especially the Pharisees, had all of that. It took a greater righteousness. It took that which came from a changed heart. That was true righteousness

Jesus was setting up an impossible barrier to works-salvation. The only thing that God accepts is the perfect righteousness of God that is imputed to all who believe (Genesis 15:6; Romans 4:5).


There is an old poem that might help summarize Jesus' teaching on the Law, as well as what we find in the rest of Scripture. It is attributed to John Bunyan, the writer of the book 'Pilgrim's Progress', although we aren't sure that he was the one who actually penned this poem. It tells us:

"Run, John, run, the law commands
But gives us neither feet nor hands,

Far better news the gospel brings:
It bids us fly and gives us wings."

We can thank God for the Law, because it showed us the holy standards that He expects of us as His creation, formed in His image. . And through that it reveals to us what great sinners we are and how far we are away from His righteousness.

Reading the Law, found in the Old Testament, should give us all a renewed appreciation of just what Jesus did for us on the cross of Calvary. He who knew no sin, who kept the Law perfectly, became sin for us that we might be made the righteousness of God in Him (II Corinthians 5:17).

If you are relying on keeping the law or any other form of works to get you into a right relationship with God and give you a home in heaven, then you are on an impossible mission. It is like jumping across the Grand Canyon on a motorcycle and hoping to get to the other side safely. Even if you miss it by an inch, you still die!

Accept Jesus Christ today. He is the only one capable of saving you and getting you safely into eternity.

Let us thank God for His perfect and holy law. For without it we wouldn't have known our need for a perfect and holy Savior.

© 2021 Jeff Shirley

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