“Therefore whoever abolishes one of the least of these commandments and teaches people to do so will be called least in the kingdom of heaven, but whoever keeps them and teaches them, this person will be called great in the kingdom of heaven. For I say to you that unless your righteousness greatly surpasses that of the scribes and Pharisees, you will never enter into the kingdom of heaven.”
This is often interpreted as a sort of works salvation, claiming law-breaking as grounds for exclusion from the Kingdom. Verse 20, which says our righteousness must exceed that of the Pharisees or we “will certainly not enter the Kingdom of heaven” (NIV) is a strong contributor this this view. The phrase translated ‘certainly not’ here is a strong emphatic negative (Dana & Mantey). It is a way of saying, “In this condition, this will absolutely not happen.” So one with a righteousness not exceeding the Pharisees is out of luck for entrance to the Kingdom.
Yet, does the passage say that breaking the commands of the law, or teaching others to break them will keep one out of the Kingdom? Actually it does not. It says one must have righteousness greater than the Pharisees, but what this means is explained in the following passages when Jesus gives the commands of the law a deeper and internal meaning—anger equivalent to murder, lust equivalent to adultery, etc. Verse 19 is important to understand because it is this verse which discusses breaking commands and teaching others to break them. However, it never says such behavior is grounds for exclusion from the Kingdom. It says those who do these things “will be called least in the Kingdom of heaven.” This is not a statement about how to enter the Kingdom. It is a statement of status among those who are included in the Kingdom. Jesus does not make law-keeping the basis for entrance to the Kingdom. But what about verse 20 when he says those without righteousness greater than the Pharisees will never enter the Kingdom? Since having insufficient righteousness (not greater than the Pharisees) is grounds for exclusion, but breaking the commands of the law changes one’s status within the Kingdom but does not exclude one, the two must not be synonymous terms. In this way we see that Jesus cannot be defining ‘righteousness greater than the Pharisees’ as law-keeping.
The rest of the passage explains that this righteousness is from within. It flows from being a changed person—one who does not unjustly get angry or wrongly respond in anger; one who does not look with lust upon another; one who has no need to make oaths or pledges of right behavior or truth. Such righteousness is greater than that of the Pharisees because theirs is simple rote rule-following—no interior change; no new condition. True righteousness is seen in Romans 3:21a (LEB), “But now, apart from the law, the righteousness of God has been revealed…” This righteousness is not a matter of law-keeping. This righteousness is a matter of being internally changed. Such a person is more righteous than the Pharisees because the behavior springs from a changed nature—one which naturally obeys God and seeks his pleasure.
This picture of the changed nature fits perfectly with Jesus’ description of true righteousness in the remainder of Matthew five. It is this righteousness which Jesus works in us. It is this change which makes us citizens of the Kingdom, not law-keeping.
“So then, the law became our guardian until Christ, in order that we could be justified by faith. But after faith has come, we are no longer under a guardian.” Galatians 3:24f (LEB)