Jesus taught that all who follow Him are to be salt and light in this world (Matt 5:13-16). In fact, it’s as we live like Jesus, unbelievers will trust in the gospel and God will be glorified (Matt 5:16). But what does it mean to live like salt and light? How are we to do that? 

In order to answer that question, Jesus directs His listeners to the Word of God. And in Matthew 5:17-21 Jesus gives 4 truths on how to use God’s Word so we will live as salt and light in this world. 

Truth #1: Jesus is the fulfillment of the O.T. 

In verse 17, the words, “Law or the Prophets” refer to the entire O.T. The O.T. is not to be dismissed or neglected with the coming of Jesus. Rather, we are to understand that Jesus comes as the one who fulfills all that the O.T. anticipated.  What this means it that we will only truly understand the O.T. when we see that it points to Jesus. Jesus applied this truth in Luke 24:26–27 when walking with the two disciples on the Emmaus road:

²⁶ Was it not necessary that the Christ should suffer these things and enter into his glory?” ²⁷ And beginning with Moses and all the Prophets, he interpreted to them in all the Scriptures the things concerning himself.

Truth #2: Every part of the O.T. is significant. 

In verse 18, Jesus said, “For truly, I say to you, until heaven and earth pass away, not an iota, not a dot, will pass from the Law until all is accomplished.” The word “iota” refers to the smallest letter in the Greek Alphabet. And the word “dot” refers to the small marks that distinguish on letter from another. Jesus’ point is that every promise in the O.T. will be fulfilled in Jesus. Nothing will fail! He is encouraging us to read and know and believe every Word in the Bible. 

Truth #3: Teach everything. 

This truth logically come from the previous truth. If every word of God is truthful and will come to pass, then we need to teach every word. There is not one command in the Bible that should be neglected or ignored. In fact, Jesus said whoever fails to teach even one of the commands will be called least in the Kingdom. Jesus is not trying to scare anyone from teaching, but rather He is calling us to proclaim the whole counsel of God. But we must remember truth #1: Jesus is the fulfillment of the O.T. This means that if we are to rightly teach God’s Word, then we must do so in light of who Jesus is, what He has done at the cross, and what He will do at His return. For example, do we need to still offer animal sacrifices for our sins? No we do not, for Jesus has come as the Perfect High Priest who offered Himself as our perfect sacrifice so we can be forgiven. We see this truth in Hebrews 9:13–14 (ESV), ¹³ For if the blood of goats and bulls, and the sprinkling of defiled persons with the ashes of a heifer, sanctify for the purification of the flesh, ¹⁴ how much more will the blood of Christ, who through the eternal Spirit offered himself without blemish to God, purify our conscience from dead works to serve the living God.

Truth #4: Read for Transformation.

Jesus commands all of His followers to be more righteous than the Pharisees. He said if our righteousness does not exceed that of the scribes and pharisees “you will never enter the Kingdom of heaven.” Now Jesus is not prescribing a works-based salvation. That would go against the clear teaching of Scripture (see Eph 2:8-9). In Matthew 23 we gain an accurate understanding of the righteousness of the Pharisees and Scribes. Matthew 23:25–28 (ESV)

²⁵ “Woe to you, scribes and Pharisees, hypocrites! For you clean the outside of the cup and the plate, but inside they are full of greed and self-indulgence. ²⁶ You blind Pharisee! First clean the inside of the cup and the plate, that the outside also may be clean. ²⁷ “Woe to you, scribes and Pharisees, hypocrites! For you are like whitewashed tombs, which outwardly appear beautiful, but within are full of dead people’s bones and all uncleanness. ²⁸ So you also outwardly appear righteous to others, but within you are full of hypocrisy and lawlessness.

The Pharisees were primarily concerned with how they appeared before man. They did not see themselves as sinners in need of a Savior. But Jesus is not calling us to simply perform outward acts of obedience. Rather, he wants us to read God’s Word that we would be transformed from the inside out. It’s as we come to God’s Word by faith that we are transformed by degree by degree into the very image of Jesus (2 Cor. 3:18). 

So how do we live as salt and light in the world? We commit to studying God’s Word realizing that it ultimately points us to Jesus and transforms us to become more like Jesus. The rest of Matthew 5 gives practical examples of being transformed by God’s Word into the image of Jesus.