Sermon: Sunday, 9th November, 2025
Speaker: John Johnstone
Scripture: Matthew 5:17-20
If we want to grow and develop as Christians, is it important that we understand the place of God’s law in our lives. God’s law is summarised in the 10 commandments, and these commandments are summarised by Jesus in one words – love.
‘Hearing that Jesus had silenced the Sadducees, the Pharisees got together. One of them, an expert in the law, tested him with this question: ‘Teacher, which is the greatest commandment in the Law?’ Jesus replied: ‘Love the Lord your God with all your heart and with all your soul and with all your mind.’ This is the first and greatest commandment. And the second is like it: ‘Love your neighbour as yourself.’ All the Law and the Prophets hang on these two commandments.’ (Matthew 22:4-40)
So, Jesus reminds us that the law is good and is really concerned with how we can love God and love one another. We can also see just how good the law is by understanding that it reflects the character of God himself. For example, God tells us not to lie as he is the God of truth and he tells is not to commit adultery because he is a faithful God. The problem all human beings have is not that the law is bad or irrelevant. It is good and extremely relevant. The problem is that we are unable to keep the law in our own strength. In that sense, the law is like an x-ray, which shows all the moral failures we have inside our hearts. So, when we hear the simply command not to be jealous of what other people have- do not covet- we begin to realise that we are experts in coveting, and that is a serious problem.
When it comes to the commandments of God, Christians often fall into two dangerous extremes. Some wrongly believe that the law no longer applies to the Christian. They say things like, ‘We are now no longer under law but grace.’ or ‘I don’t need to keep the law – Jesus has forgiven me.’ This is wrong. They will twist a few New Testament verses to try and justify this position. Yes, we know that we cannot be justified or get to Heaven through keeping the law, but nonetheless it still has an important place in our lives. This view is called antinomianism, which just means ‘against the law’. I hope none of us here thinks that the 10 commandments or the beatitudes no longer apply.
The other extreme when it comes to the law is legalism. Legalists focus on keeping the law outwardly but often ignore the need to keep the law in our hearts. By doing this they try and ‘domesticate’ the law, reducing its power and making it something manageable, something that they can keep really easily. This too is wrong. Legalists sometimes think they can earn God’s favour by rule-keeping and they also have a tendency to add human traditions on top of God’s law.
Sinclair Ferguson: ‘The legal spirit is not to be confused with the Spirit of holiness. It is a subtle distortion that leads us to think that God’s approval of us is conditioned upon our obedience rather than upon Christ’s obedience.’
Our passage today, just 4 verses, is extremely helpful because here Jesus explains what his relationship is to God’s law, and then teaches us what our relationship with the law ought to be.
1. Jesus’ relationship with the law of God
This section begins with Jesus saying, ‘Do not think that I have come to abolish the Law or the Prophets…‘ (Matthew 5:17) Clearly, for Jesus to have said this, some people did think, wrongly, that Jesus was against the law. Why did they think that? Well, when Jesus picked ears of corn on the Sabbath or healed the sick on the Sabbath the Pharisees and teachers of the law got extremely angry with him. They thought Jesus was breaking the Sabbath commandment. However, he was not. Jesus was only breaking the human traditions they had added to the Bible, but he would never have broken a commandment. He was perfect. It was their made-up rules which were wrong, not Jesus! Or when Jesus ate and drank with tax collectors or prostitutes, the religious leaders thought Jesus was breaking the commandments. But again, they were wrong. He was only breaking their human traditions and false interpretations of the law. In any case, Jesus knows some people have been claiming that he is against the law.
And Jesus wants to make his relationship to the law crystal clear. He says, ‘I have not come to abolish them but to fulfil them.’ (Matthew 5:17) What does he mean?
Before we consider how Jesus fulfils the God’s law, let’s first just hear his plain and powerful affirmation of the moral law in the Old Testament. He says it has not been abolished. It still stands. So, as we continue in our studies on discipleship, know that Jesus expects all his followers, in God’s strength, to keep his law. We must try to honour our parents and keep his day and not tell lies. Those people (antinomians) who claim we are no longer obliged to keep the law are wrong.
How does Jesus fulfil the law and the prophets? This is a wonderful thing to consider. The phrase ‘the law and the prophets’ is just another way of speaking about the whole of the Old Testament. Jesus fulfils the Old Testament as he fulfils the many predicative prophecies there made about him. What was predicted would happen to the Messiah, predictions made hundreds of years before Jesus’ birth, came to pass in Jesus. It was prophesied that the Messiah would be born of a virgin, born in Bethlehem, but would go down into Egypt for a time. All of this happened to Jesus. He fulfilled these prophesies. Throughout Matthew’s gospel, as things happen to Jesus, he reminds us of this by saying: ‘This happened to fulfil what was written in the prophet so and so.’
Let’s just pause here. How do we know the Bible is a supernatural book coming straight from the mouth of God? How do we know we can trust what is written there? One massive reason is this – there are hundreds of predictions about Jesus written hundreds of years before his birth and they all came true. All of them. It was predicted that he would be crucified with criminals, be offered wine vinegar to drink, be buried in a rich man’s tomb and then rise from the dead. All of these things came to pass. Let’s have confidence in the Bible. It is not a book where God explains everything to us exhaustively. He does not answer all our questions. However, in his wisdom, he has revealed so much to us- all that he wants us to know. Even conservatively speaking, Jesus fulfilled over 300 prophecies.
But Jesus also fulfils the law in another sense – he shows us how deep God’s law really is. It is not just a matter of something external but it is a matter of the heart. If you think of God’s law as a bike tyre, the Pharisees had actually deflated the law of its power by only keeping it on the surface. Jesus comes and puts air back into the tyre, filling up the law so that we can see its true significance. For example, the Pharisees thought they could keep the 7th commandment – do not commit adultery. They thought they were good people and that this law was manageable. Jesus smashes this falsehood by saying: ‘You have heard that it was said, ‘You shall not commit adultery.’ But I tell you that anyone who looks at a woman lustfully has already committed adultery with her in his heart. (Matthew 5:27-28) This is crucial to grasp. Jesus shows the law concerns our motives and thought -lives and hearts and not just outward appearance. Man looks to the outward appearance but God looks to the heart.
Ironically, the religious leaders had accused Jesus of abolishing or weakening the law. In fact, it was they who had weakened it, by ignoring our need to have our hearts right with God.
Sinclair Ferguson: ‘Jesus did not weaken the law. On the contrary, he let it out of the cage in which the Pharisees had imprisoned it, allowing it to pounce on our secret thoughts and motives and tear to pieces our bland assumption that we are able to keep it in our own strength.’
What’s the practical lesson here to take away this morning? When we read the Old Testament, there are some laws that no longer apply, and for good reason. For example, the ceremonial laws for priests concerning how to sacrifice animals no longer apply today because Jesus is the ultimate sacrifice and has fulfilled the ceremonial law. It is no longer required. And there are also Old Testament laws which were specifically for Israel as a nation. For example, the food laws, not to eat pork. These laws are no longer in force as God’s people no longer constitute a nation. But all the other Old Testament laws are still in force for us, and Jesus’ followers must seek to obey these moral laws.
Jesus is so strong on this. He says that the moral law is as enduring as the universe itself. ‘For truly I tell you, until heaven and earth disappear, not the smallest letter, not the least stroke of a pen, will by any means disappear from the Law until everything is accomplished.‘ (Matthew 5:18) God’s law remains in force.
Imagine you are reading through Deuteronomy and you read in chapter 15: ‘If among you, one of your brothers should become poor… you shall not harden your heart or shut your hand against your poor brother, but you shall open your hand to him.’ (Deuteronomy 15:7-8) Friends, these moral principles of open-handed compassion still apply to me and to you. The same goes for laws about justice, and care for the vulnerable, especially widows, orphans and foreigners.
2. The Christian and the law of God
Let’s start by considering Jesus’ shocking statement: ‘For I tell you that unless your righteousness surpasses that of the Pharisees and the teachers of the law, you will certainly not enter the kingdom of heaven.’ (Matthew 5:20) Most ordinary Jews regarded the Pharisees and the teachers of the law as the most righteous people on the planet. If anyone would get into Heaven, they wrongly thought, it would be them. They were the experts. The knew the law inside out and seemed to keep the 248 commands and 365 prohibitions. Please understand how flabbergasted the people would have been to hear the standard of righteousness must exceed theirs. Does this mean that we need almost perfection to be good in God’s eyes? No!
The truth is, as we have seen, that the quality of the Pharisees’ rule-keeping was so surface-level that they were not righteous at all. They actually distorted God’s commands, twisted them, and like everyone else failed to keep them. To help us understand this, remember the rich young ruler in Matthew 19. Jesus reads him the commands, and the ruler says: ‘All these I have kept’. He looked like a good person externally but inwardly he loved money more than God. Jesus tells him to go and sell his possessions and give the money to the poor. He cannot do it. Money is his God. He cannot even keep the first commandment. He is not righteous. Our righteousness must be greater than his.
How can we do this? How can our righteousness be greater than that of the Pharisees? Some must have thought that Jesus was joking! Here is the answer. We can only do this by having a heart-righteousness. And a deeper heart-righteousness is impossible for us unless we are given a new heart by God himself. And we only get a new heart following a new spiritual birth- being ‘born again’.
Here’s the wonderful process – when we turn from our sins and trust in Jesus for our salvation and follow him, God gives us a new heart, and this heart begins to want to keep God’s laws, not to earn his love, but because of our gratitude to him. Our new heart obeys God out of gratitude. This is the opposite of why the Pharisees tried to keep the law. This should not be a surprise to us. We read in Ezekiel, ‘I will give you a new heart and put a new spirit in you; I will remove from you your heart of stone and give you a heart of flesh. And I will put my Spirit in you and move you to follow my decrees and be careful to keep my laws.’ (Ezekiel 36:26-27)
For all of Jesus disciples here this morning, our righteousness does exceed that of the Pharisees. Is this something we can boast about? Absolutely not. It is God who gave us new hearts and it is God who gave us his Spirit who helps us to love and keep the law. Without God’s help, without conversion, no one is able to keep God’s law out of gratitude to God. We need God’s help to keep the beatitudes and the 10 commandments and any other aspect of the moral law.
We also see this clearly in Jeremiah, ‘This is the covenant that I will make with the people of Israel after that time,’ declares the Lord. ‘I will put my law in their minds and write it on their hearts. I will be their God, and they will be my people.’ (Jeremiah 31:33)
Here’s the before and after. Before salvation, God’s law is something external and burdensome. After salvation, we understand more of its depth and we have a God-given desire to keep it, fuelled by our love for Jesus and motivated to please him.