Not only do Christians need to believe the Bible and stand on it as a matter of principle, they need to obey it and act on it too, which is the ultimate test of whether any of us actually believe God’s Word or not. This is what Jesus addresses when He says, “Whoever relaxes one of the least of these commandments and teaches others to do the same will be called least in the kingdom of heaven, but whoever does them and teaches them will be great in the kingdom of heaven.”

The disciples were learning from Jesus, but before long the disciples would be teaching others in Christ’s name. When that day came, they would need to be sure they were teaching God’s Word and not their own ideas or anything that might lead others to break God’s law. They would be judged on whether they lived and taught what God had commanded. All Christians will be judged by this measure. Jesus suggested this when he spoke about anyone who might mislead God’s children: “It would be better for [such a person] to be thrown into the sea with a millstone tied around his neck than for him to cause one of these little ones [young/new believers] to sin” (Luke 17:2).

Matthew 5.19 is mostly negative, addressing the failure to practice and teach what is right. In the last verse of this section, we come to what is positive. But strikingly, the positive is no more encouraging than the negative. It is stunning, sobering, even frightening in its rigor. “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.” More even than the Pharisees and teachers of the law? Aren’t they the most upright and moral of all people? Aren’t they known everywhere for their good works?

Jesus’ statement is especially sobering in contrast to what He has just said. In the preceding verse He said that failing to practice the law or teaching others to break it would result in a dishonorable place in God’s kingdom. But here He says that without a righteousness surpassing even that of the Pharisees and teachers of the law, the alleged disciple will have no place in God’s kingdom at all.

What is the righteousness referred to in verse 20? On the one hand it is the divine righteousness that comes to us by God imputing it to us on the basis of Jesus’ death – imputed righteousness. We do need that righteousness. Without it we are lost. But this is not the way “righteousness” is used in Matthew’s Gospel generally. In Matthew, “righteousness” means an actual conformity to God’s demands in Scripture, both externally and also internally, as the next verses in the Sermon on the Mount will show. But how are we to match that to what we have heard about justification through Christ’s work on our behalf?

The answer is that although justification by the imputed righteousness of Christ is the core of the Gospel and utterly essential – Luther called it “the doctrine by which the Church stands or falls”—it is not the whole of the Gospel, and it is not what Jesus is talking about here. It is true that God justifies the ungodly on the basis of Christ’s work, but that is not all God does. God also regenerates the one who is being justified. Thus, there is no justification without regeneration, just as there is no regeneration without justification. The important point is that the re-created person will actually live a moral life superior to that of the Pharisees.

Regeneration is what Jesus was talking about when he told Nicodemus, “You must be born again” (John 3.7). It is what Paul was writing about when he told the Ephesians, “God … made us alive with Christ even when we were dead in our trespasses” (Ep.2.4–5). On the basis of this distinction, Paul then speaks of two kinds of works, those we are capable of by ourselves (like the righteousness of the Pharisees) and those that are produced in us by the new life of Christ within.

Paul wrote, “For it is by grace you have been saved, through faith – and this not from yourselves, it is the gift of God – not by works, so that no one can boast. For we are God’s workmanship, created in Christ Jesus to do good works, which God prepared in advance for us to do” (Ep.2.8–10). As D. A. Carson rightly observes, “Verse 20 does not establish how the righteousness is to be gained, developed or empowered; it simply lays out the demand.”

How then is this superior, practical righteousness to be gained, developed, and empowered? It is by coming to Christ, finding both justification and new life in Him, and then by obeying and serving God by God’s own power. We are not capable of obeying and serving God by our own strength. We will be able to do it only because “it is God who works in you to will and to act according to his good purpose” (Ph.2.13).

The wonderful thing about this is that when we find ourselves doing good works, we will not take credit for ourselves (which is what the Pharisees did, judging themselves to be persons who were morally superior to other people). Instead, we will give all the glory to God by whom this righteousness is attained and by whose power alone these good works can be done. Moreover, we will marvel at the wisdom of God, which made such a great salvation possible, and we will say, as Paul did in Romans, “To him be the glory forever! Amen” (Romans 11.36).