Christ Fulfills the Law – Matthew 5:17-20

In this fourth part of my series on the Sermon on the Mount, we’ll look at a passage that does present some challenges. The biggest challenge is in understanding how Jesus fulfills the Law and prophets. First, let’s look at this passage in its entirety.

17 “Don’t assume that I came to destroy the Law or the Prophets. I did not come to destroy but to fulfill.  18 For I assure you: Until heaven and earth pass away, not the smallest letter or one stroke of a letter will pass from the law until all things are accomplished. 19 Therefore, whoever breaks one of the least of these commands and teaches people to do so will be called least in the kingdom of heaven. But whoever practices and teaches these commands will be called great in the kingdom of heaven.  20 For I tell you, unless your righteousness surpasses that of the scribes and Pharisees, you will never enter the kingdom of heaven.” (HCSB)

As we proceed through the verses, we’ll be concentrating on four themes found within this passage.

  • The Law and how Jesus fulfills it.
  • The authority of Scripture in its entirety.
  • The Pharisees and scribes.
  • The righteousness required to enter the Kingdom of Heaven.

Verse 17: Don’t assume that I came to destroy the Law or the Prophets. I did not come to destroy but to fulfill. 

This is the most challenging verse in the passage and the one that generates the most discussion amongst theologians. First, let’s define the Law.

The Jewish understanding of the Law.

  • The Ten Commandments.
  • First five books of the Bible, the Pentateuch.
  • The Law and the Prophets, literally the entire Old Testament.
  • Oral or scribal law – in Jesus’ time, the most common understanding of the word “law,” 613 commandments created by the religious leaders.

Jesus is focused on the entire Old Testament when He talks about fulfilling the Law and prophets. At the same time, His condemnation of the religious leaders focuses on the oral law that puts additional requirements on the people. The religious leaders had introduced legalism, creating burdens instead of interpreting the principles behind the Law and focusing on practical application.

In the OT there are few rules and regulations, instead they contain rather broad principles.

  • The Ten commandments listed principles.
  • The religious leaders wanted details.
  • Scribes reduced the principles to thousands of rules and regulations. As an example: To write was to work on the Sabbath. But writing has to be defined. So, the definition runs: ‘He who writes two letters of the alphabet with his right or with his left hand, whether of one kind or of two kinds, if they are written with different inks or in different languages, is guilty. Even if he should write two letters from forgetfulness, he is guilty, whether he has written them with ink or with paint, red chalk, vitriol, or anything which makes a permanent mark. Also, he that writes on two walls that form an angle, or on two tablets of his account book so that they can be read together is guilty … But, if anyone writes with dark fluid, with fruit juice, or in the dust of the road, or in sand, or in anything which does not make a permanent mark, he is not guilty … If he writes one letter on the ground, and one on the wall of the house, or on two pages of a book, so that they cannot be read together, he is not guilty.’ That is a typical passage from the scribal law; and that is what orthodox Jews regarded as true religion and the true service of God (Barclay).
  • Jesus was not talking about these “rules” when He mentions the Law.

The point of Jesus’ teaching here, and in other passages of Scripture, is to understand the principles behind the instruction and apply them. An area that the religious leaders had failed in miserably.

Now let’s look at how Jesus fulfills the Law and prophets.

  • Fulfill does not mean “bring to an end.”
  • It means to fill out or expand the understanding (Weber). The Greek word is pleroo.
  • Jesus was not adding or taking away from the law; He was clarifying its meaning as its original author. John 1:1 In the beginning was the Word, and the Word was with God, and the Word was God.
    • This was in contrast to the religious leaders who added to Scripture through the oral tradition.
    • Israel had lost some/most of its understanding of the Law through those oral traditions.
  • How does Jesus fulfill the Law?
    • By keeping it perfectly.
    • Providing a way of salvation that meets all the righteous requirements of the law.
      • Jer 31:31-34: 31 “Look, the days are coming”—this is the Lord’s declaration—“when I will make a new covenant with the house of Israel and with the house of Judah. 32 This one will not be like the covenant I made with their ancestors when I took them by the hand to bring them out of the land of Egypt—a covenant they broke even though I had married them”—the Lord’s declaration. 33 “Instead, this is the covenant I will make with the house of Israel after those days”—the Lord’s declaration. “I will put My teaching within them and write it on their hearts. I will be their God, and they will be My people. 34 No longer will one teach his neighbor or his brother, saying, ‘Know the Lord,’ for they will all know Me, from the least to the greatest of them”—this is the Lord’s declaration. “For I will forgive their wrongdoing and never again remember their sin.”
      • Ezek 36:26-27: 26 I will give you a new heart and put a new spirit within you; I will remove your heart of stone and give you a heart of flesh. 27 I will place My Spirit within you and cause you to follow My statutes and carefully observe My ordinances.
    • By dying on the cross and canceling the claims of the law against all who submit to His lordship (Boice).
    • The Bible is about Jesus and how He fulfills what is written in it.
      • Jesus fulfills the moral law through obedience.
      • Jesus fulfills the Messianic prophecies by the events in His life. Here are a few of them.  
        • Gen 3:15: I will put hostility between you and the woman, and between your seed and her seed. He will strike your head, and you will strike his heel.
        • Gen 22:18: And all the nations of the earth will be blessed by your offspring because you have obeyed My command.
        • Ps 22:16-18: For dogs have surrounded me; a gang of evildoers has closed in on me; they pierced my hands and my feet. I can count all my bones; people look and stare at me. They divided my garments among themselves, and they cast lots for my clothing.
        • Ps 16:10: For You will not abandon me to Sheol; You will not allow Your Faithful One to see decay.
        • Isa 53: Who has believed what we have heard? And who has the arm of the Lord been revealed to? He grew up before Him like a young plant and like a root out of dry ground. He didn’t have an impressive form or majesty that we should look at Him, no appearance that we should desire Him. He was despised and rejected by men, a man of suffering who knew what sickness was. He was like someone people turned away from; He was despised, and we didn’t value Him. Yet He Himself bore our sicknesses, and He carried our pains; but we in turn regarded Him stricken, struck down by God, and afflicted. But He was pierced because of our transgressions, crushed because of our iniquities; punishment for our peace was on Him, and we are healed by His wounds. We all went astray like sheep; we all have turned to our own way; and the Lord has punished Him for the iniquity of us all. He was oppressed and afflicted, yet He did not open His mouth. Like a lamb led to the slaughter and like a sheep silent before her shearers, He did not open His mouth. He was taken away because of oppression and judgment; and who considered His fate?  For He was cut off from the land of the living; He was struck because of my people’s rebellion. They made His grave with the wicked and with a rich man at His death, although He had done no violence and had not spoken deceitfully. 10 Yet the Lord was pleased to crush Him severely.  When You make Him a restitution offering, He will see His seed, He will prolong His days, and by His hand, the Lord’s pleasure will be accomplished. 11 He will see it out of His anguish, and He will be satisfied with His knowledge. My righteous Servant will justify many, and He will carry their iniquities. 12 Therefore I will give Him the many as a portion, and He will receive the mighty as spoil, because He submitted Himself to death, and was counted among the rebels; yet He bore the sin of many and interceded for the rebels.
      • Fulfills the sacrificial system by His once-and-for-all atonement.

When looking at the Ten Commandments, the principles can be summed up by the words reverence and respect. All law is based upon them. They are the permanent stuff of our relationship to God and others. These are the foundations of Jesus’ message.

Verse 18: For I assure you: Until heaven and earth pass away, not the smallest letter or one stroke of a letter will pass from the law until all things are accomplished.

It starts with “For I assure you.” When Jesus uses this phrase or a similar one depending on what Bible version you’re using, it’s a notice to stop and listen.

The main focus here is the absolute authority and inerrancy of Scripture. Let’s look at Jesus’ views on Scripture.

  • It had supreme authority over life.
  • If a practice was in agreement with Scripture, it must be continued.
  • If it went against Scripture, it must be changed.
  • Even the smallest part is important; you can’t pick and choose which you like and want to follow. Many facets of liberal theology fail in this area.
  • Jesus often quoted Scripture in His debates or to support what He had said.
  • He submitted to Scripture.
  • Followers of Christ must follow His example regarding how Scripture is viewed.

Jesus is also refuting the claim levied by the religious leaders that He was undermining Old Testament Law.

In today’s world, biblical authority and truth are under attack. The enemy uses three main methods to undermine biblical authority.

  • An appeal to tradition.
    • This was the main problem in Jesus’ day.
      • Rabbinical traditions had distorted the Law.
      • Traditions throughout church history have distorted the truth of Scripture.
    • The Roman Catholic church did the same thing.
      • Protestant reformation, sola Scriptura…Scripture alone, not a sinful man, the Pope, as a leader.
      • Tradition had replaced the truth of Scripture.
      • Is that a problem in today’s church?
  • Elevate reason above revelation, a method of liberal theology.
    • Measure it against reason.
    • Judge it by scientific or historical assumptions. The 18th-century enlightenment ushered in this method.
  • Rejecting the Bible’s sufficiency or absolute truth.
    • This is an issue with the modern church, which often uses “signs and wonders,” such as the seeker-sensitive movement, which turns a worship service into an entertainment spectacle.
    • Working in secular ways produces secular results, shallow Christians at best.
    • If you reject portions of the Bible as no longer relevant, where do you draw the line between truth and fiction?
    • Christians need to stand on the sure foundation of God’s Word, which is absolutely inerrant and infallible.

Some may ask, “what about Old Testament practices that are no longer done?”

  • As one example, let’s take the temple sacrifices to atone for sin. Death and the shedding of blood are no longer required as Jesus fulfilled that with His death on the cross. However, the penalty and payment for sin are still valid and need to be taught and understood for salvation through Jesus (Wilkins).
  • Another example, which is still a requirement for us, is to love God and our neighbors.
  • Later in this chapter, verses 21-48, Jesus will give practical examples for us to follow.
  • Instead of throwing out Old Testament instruction which seems outdated, as in the example of temple sacrifices, we need to understand the underlying principles and how they are still applicable today.

Verse 19: Therefore, whoever breaks one of the least of these commands and teaches people to do so will be called least in the kingdom of heaven. But whoever practices and teaches these commands will be called great in the kingdom of heaven. 

The word “breaks” here creates a wordplay with the term “destroy” from verse 17. It is best understood to mean “sets aside” or to “release” from having to follow (Blomberg). It is important to note that this verse is directed towards those who do follow Jesus, not the lost. Jesus gives a warning that the faithful teaching of Scripture is expected.

  • There is a duality in this verse.
    • Obedience in personal action.
    • Faithfulness in correctly teaching others.
      • There is a greater measure of judgment for teachers of the Word. James 3:1 Not many should become teachers, my brothers, knowing that we will receive a stricter judgment.
      • Misleading children, either literally as in physical age or in spiritual maturity Luke 17:2 It would be better for him if a millstone were hung around his neck and he were thrown into the sea than for him to cause one of these little ones to stumble.
  • Jesus is addressing His disciples as future teachers. Contextually, the Sermon on the Mount is a sermon to His followers.
  • It is essential that followers of Jesus teach everything in Scripture, not adding or taking anything away. Jesus will ultimately give this task in the Great Commission Matt 28:19-20 Go, therefore, and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe everything I have commanded you. And remember, I am with you always, to the end of the age.
    • Jesus is emphasizing the binding authority of Scripture.
    • His followers must do the same.
      • Follow Scripture.
      • Teach Scripture.
  • He is also condemning the Pharisees and other religious leaders for altering the Law and reminds them of their responsibility to teach others.
  • “Least” and “great” refer to Christians, not those inside or outside of the Kingdom.
    • “Least” are those who have cruised through life, not fulfilling God’s purpose.
    • “Great” are those who have been faithful to their calling (Wilkins).

Verse 20: 20 For I tell you, unless your righteousness surpasses that of the scribes and Pharisees, you will never enter the kingdom of heaven.

This statement would have been shocking to the average Jew at that time. We must remember that the religious leaders were viewed as the epitome of Judaic righteousness. But Jesus is saying that those who follow Him must surpass the righteousness of the religious leaders. In effect, it is the thesis statement for the entire Sermon on the Mount; Christian discipleship requires greater righteousness.

  • In Matthew, “righteousness” means actual conformity to God’s demands in Scripture, externally, and internally (Boice).
    • The religious leaders lived under the motivation of the law to follow its details.
    • Christians live under the motivation of love, love from and to God extended to others.
    • Righteousness must be an inside-out and not an outside-in process. Ps 51:16-17 You do not want a sacrifice, or I would give it; You are not pleased with a burnt offering.
      17 The sacrifice pleasing to God is a broken spirit. God, You will not despise a broken and humbled heart.
  • Scribes were the equivalent of a professor of biblical and theological studies.
  • Pharisees were a sect that was committed to fulfilling the demands of the OT through oral tradition.
  • Within Judaism, the Pharisees and scribes were considered the pinnacle of righteousness.
    • Jesus is not challenging their meticulous attention to the Law.
    • He is challenging their refusal to discipleship, which is following the intent of the Law (Blomberg).
    • A Jewish listener to this message would believe no one could enter heaven.
    • Even when Paul pleaded his case before Herod Agrippa, a Pharisee was considered in high esteem as Paul stated that he had lived after the strictest sect of Judaism. Acts 26:5 They had previously known me for quite some time, if they were willing to testify, that according to the strictest party of our religion I lived as a Pharisee.
  • Jesus was challenging the concept of keeping the law because the issue was with their heart.
    • An example is the Pharisees’ teaching that implied if a man avoided having sex with someone other than his spouse, then he had kept that portion of the law. Jesus, understanding the universality of human lust, filled the law out to the full by pointing out God’s original intention—because adultery is a matter of the heart, people regularly commit this sin through a single moment of lust in the mind (Weber).
    • The points Jesus makes throughout the Sermon on the Mount shows that virtually each one draws a contrast between the false righteousness of the religious leaders and the true righteousness that God desires.
    • The person who discovers and appropriates true righteousness will manifest the character qualities described in the Beatitudes (5:3–12) and will impact the world as described in 5:13–16. The Pharisees did not.
    • Jesus declared war on the false religion of the Pharisees. Not even the law-keeping Pharisees could enter heaven without a Savior.
    • Externally they looked good, but their inner self (heart) was rotten. Man looks at the outside, and God looks at the inside
      • 1 Sam 16:7  But the Lord said to Samuel, “Do not look at his appearance or his stature, because I have rejected him. Man does not see what the Lord sees, for man sees what is visible, but the Lord sees the heart.”
      • Matt 23:27 “Woe to you, scribes and Pharisees, hypocrites! You are like whitewashed tombs, which appear beautiful on the outside, but inside are full of dead men’s bones and every impurity.”
    • Everyone needs heart surgery Ps 51:10 God, create a clean heart for me
      and renew a steadfast spirit within me.
  • Even here, Jesus’ words either draw people to Him or cause them to react in hatred and spurn Him.
  • Consider what Paul, a Pharisee among Pharisees, wrote towards the end of his life in Phil 3:4-9 although I once also had confidence in the flesh. If anyone else thinks he has grounds for confidence in the flesh, I have more:circumcised the eighth day; of the nation of Israel, of the tribe of Benjamin, a Hebrew born of Hebrews; regarding the law, a Pharisee;regarding zeal, persecuting the church; regarding the righteousness that is in the law, blameless.But everything that was a gain to me, I have considered to be a loss because of Christ.More than that, I also consider everything to be a loss in view of the surpassing value of knowing ChristJesus my Lord. Because of Him I have suffered the loss of all things and consider them filth, so that I may gain Christand be found in Him, not having a righteousness of my own from the law, but one that is through faith in Christ—the righteousness from God based on faith.
  • Paul lists seven achievements here, four inherited and three earned (Boice).
    • Inherited.
      • Born a Jew.
      • Pure-blooded Jew, both of his parents were Jewish.
      • Circumcised on the eighth day.
      • From the tribe of Benjamin, one of the two tribes that had remained faithful to temple worship and the law.
    • Earned.
      • He was a Pharisee, the strictest sect of Judaism. It was a personal decision to become one.
      • He was a zealous Pharisee, as proved by his persecution of the church.
      • He worked so hard at his calling he actually believed himself blameless as a Pharisee before the standards of the Law.
  • However, when all was said and done, Paul viewed all of it as worthless apart from knowing Christ.


  • Are we legalistic, or do we apply principles that are contained in Scripture? Too often, being legalistic, besides it being a wrong approach, drives away our spiritual brothers and sisters, as well as those who may be seeking to learn more about Jesus. There are two avenues to evangelism. The first is the informational Gospel message, what is contained in the Bible. The second is the incarnational Gospel message, how we live as followers of Christ. If we share the information about God’s love for us, but our lives don’t demonstrate that same love as we interact with the world around us, we are hypocrites. This also often drives people away. Jesus always met the lost where they were and tried to bring them to where they needed to be, a loving relationship with God. This does not mean we tolerate sin; we address it in a spirit of love, whether it is a member of our spiritual family who has fallen into sin or a lost person. This is an area where many churches and individuals fail. There is no better example than the narrative of the woman caught in adultery. Jesus didn’t condemn her. He showed love and compassion but also said, “go and sin no more.”
  • Do we believe in the absolute authority of Scripture? That it is inerrant and infallible? This topic is a dangerous slippery slope. If we start to doubt a section of the Bible, where does it stop? Pandora’s box has been opened; we can start questioning any section of Scripture that we don’t feel comfortable with. From earlier in this lesson, we read that Jesus is the Word. Jesus is true and perfect. Therefore, the Word is true and perfect.
  • Are we faithful in following and teaching what is in Scripture? Knowing what is in Scripture, head knowledge, if not accompanied by heart knowledge and transformation, does not lead to salvation. James 2:19 You believe that God is one, you do well. The demons also believe – and they shudder. The demons have head knowledge about God, but that won’t save them. We need to be doers of the Word and not just hearers. Then, we need to teach others. Jesus gives us that command in the Great Commission; we are to teach ALL that is contained in Scripture without adding or taking away from it.
  • Do we understand that our heart condition and our identity in Jesus are important? Not what the world values but what God values. Our identity is found in Jesus and nowhere else. The world says that our titles, jobs, income, neighborhood, education, car, house, or our success are what matters most. Pursuing those rob you of joy as you will never be satisfied, you will always want the next step up from wherever you are or whatever you have. We all are in need of heart surgery to remove the idols from our lives. However, when we know that we are loved and valued by the creator of the universe what more is needed? He loved us enough to send Jesus to die on the cross for us. His desire is that all would be saved. We realize that what the world tells us is nothing more than a lie. Instead of focusing on what we don’t have, we should be thankful for what we do have. And if our identity is in Jesus, do we really need anything else?

3 thoughts on “Sermon on the Mount Lesson Four

      1. I could tell that you would have had to have had seminary because the only people I have every met to lay out 3 verses in the manner that you did had been to seminary. I am looking to finish my studies. I have a ministry degree but I really would like a graduate level one.
        Yours in Christ, A Christian Dad


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