Understanding Matthew 5:17-20: Fulfilling the Law

Context and Meaning of Matthew 5:17-20

Right after the Beatitudes and before launching into deeper teachings on anger, lust, and love for enemies, Jesus makes a clear statement about His relationship to the Old Testament law.

In Jesus’ day, 'the Law and the Prophets' meant the entire Old Testament - the sacred writings that guided Jewish life and faith. When Jesus says He came not to abolish but to fulfill them, He means He is bringing God’s original intentions to full completion, not canceling them. This fulfillment includes both obeying the law perfectly Himself and revealing its deeper meaning, especially how it applies to our thoughts and motives, not merely our actions.

This sets the stage for what follows, where Jesus unpacks commandments about murder, adultery, and love, showing that true righteousness goes far beyond rule-following - it requires a transformed heart.

Fulfilling the Law: Jesus' Radical Reinterpretation of Righteousness

Building on Jesus’ declaration that He fulfills the Law, this passage reveals a significant tension: He upholds the Law’s permanence while simultaneously redefining what it means to truly obey it from the heart.

When Jesus says not a single 'iota' or 'dot' will pass from the Law, He’s using vivid imagery - 'iota' refers to the smallest letter in the Greek alphabet, like our 'i', and 'dot' likely means the tiny stroke distinguishing similar Hebrew letters. This emphasizes that God’s standards are unchanging and exact, not one detail will be discarded. Yet immediately, He intensifies the Law’s demands. Beyond avoiding murder, you must also guard against anger and insults (Matthew 5:21-22). Beyond avoiding adultery, you must reject lust in your heart (Matthew 5:27-28). This shows that fulfillment isn’t mere legal compliance, but living out the Law’s deepest intent - Holiness that flows from inner transformation.

The scribes and Pharisees were respected for their strict rule-following, but Jesus says their righteousness isn’t enough. Why? Because theirs was often external - focused on rituals, public honor, and social status - while neglecting justice, mercy, and faith (Matthew 23:23). In contrast, Jesus calls for a righteousness that exceeds theirs, not in quantity of rules kept, but in quality of heart. This kind of righteousness is only possible through a relationship with Him, as later revealed in the New Testament: we are made righteous not by our effort, but by faith in Christ (2 Corinthians 5:21).

This deeper righteousness prepares us for what follows - Jesus’ teachings on loving enemies, giving generously, and trusting God completely. It shifts the focus from avoiding wrongdoing to actively pursuing God’s character in every area of life.

True righteousness isn’t about checking religious boxes - it’s about a heart so changed by God that love, mercy, and integrity flow naturally, even toward enemies.

The call to surpass the Pharisees’ righteousness is an invitation to live from the inside out, empowered by grace. This aligns with Jeremiah's prophecy of a new covenant written on hearts, not on stone (Jeremiah 31:33).

Living and Teaching God's Commands: A Call to Faithful Simplicity

Jesus makes it clear that following God isn’t about picking and choosing which rules matter, but about honoring His whole will with a humble heart.

He says that anyone who ignores even the least of God’s commands and teaches others to do the same will be called ‘least’ in the kingdom, while those who obey and teach them will be called ‘great’ - showing that faithful living and sharing of God’s ways brings true greatness. This isn’t about earning favor through perfection, but about a heart that respects God’s Word and wants to pass it on faithfully.

Doing and teaching even the smallest command shows where your heart truly stands in God’s kingdom.

This fits Matthew’s theme of Jesus as the ultimate teacher and fulfiller of God’s plan, calling people to a life that reflects His kingdom from the inside out.

Fulfillment of the New Covenant: From Law on Stone to Law on Heart

Jesus’ teaching in Matthew 5:17-20 makes the most sense when we see it as the beginning of a new era - one foretold by the prophet Jeremiah.

Long before Jesus came, God promised through Jeremiah, 'I will put my law within them, and I will write it on their hearts. And I will be their God, and they shall be my people' (Jeremiah 31:33). This new covenant transformed how the old rules are lived. They became internal convictions rather than merely external commands. And in Galatians, Paul calls this the 'law of Christ' (Galatians 5:14), fulfilled in loving others as He loved us.

Jesus fulfills the Law not by adding rules, but by writing God’s ways on our hearts through the promise of a new covenant.

So Jesus isn’t lowering the bar or raising it to make it harder. He’s showing how the Law finds its true purpose in a heart changed by grace, setting the stage for His ultimate act of love on the cross.

Application