Matthew 5:13-20: Salt, Light, and the Bible

Devotionals > New Testament > Matthew > Matthew 5:13-20: Salt, Light, and the Bible

Matthew 5:13-20: Salt, Light, and the Bible

January 11, 2021


Genesis 27-28, Psalm 11, Matthew 5:13-20, Acts 7:1-38

Matthew 5:13-20:

This part of the Sermon on the Mount, in the section we are reading this morning, comprises two distinct sections, aims, and goals.  

In the first, verses 13-16, Jesus is thinking about the witness, the lifestyle, the impact on the world, of this little fledging group of disciples, and he is teaching them about that and what it means to shine their light in the world.  

In the second section, verses 17-20, Jesus is countermanding a false impression that might be given by his authoritative style of teaching: he is not undermining or denying or undoing anything that has been written so far in the Bible (in what we call the Old Testament, aka the Law and the Prophets), but instead is fulfilling it all. Let’s look very briefly at these two sections separately. 

In the first, Jesus has two metaphors: one is salt, the other is light. Salt in the ancient world was used to keep meat from going bad. So, to be the “salt of the world” means to be (what I have called) a “global moral preservative.” The Christian community is to function in such a way that it stops, or at least slows down the rate of, decay in society around about. This is part of our witness: practical action that acts as a moral preservative and prevents the world from “going bad.” It is like calling Christians a refrigerator: they are salt.  

The other metaphor is of “light”; once again, it refers to “good deeds,” but here the “good deeds” do not mean merely action as opposed to spoken good deeds but the whole gambit. Similarly, Jesus is saying let your light shine, don’t hide it, don’t disguise it; you have something that the whole world needs to see. We are, as I have called it, then, also to be “global spiritual illuminators.” We are pointing people to the meaning of life, giving spiritual light to those who are otherwise in darkness. By contrast, we are not to “lose our taste” (that is become corrupted morally), nor are we to hide our light (that is stop witnessing to the Great Light, that is Jesus). It is interesting that salt, as in sodium chloride, cannot chemically speaking “lose its saltiness”; but salt can become tarnished by its combination with mud and dirt and other ways of spoiling our moral influence on the world. 

In the second section, Jesus countermands a false impression that his authoritative style of teaching might have suggested that he is denying or going against the Law and the Prophets—a summary term for the Old Testament Scriptures. Instead, he has come to fulfill them. What they spoke about is who he is, and what he teaches is in fulfillment of what they are teaching. This is a very important principle for us to understand today.  

People misunderstand the Old Testament when it is interpreted in any way other than being fulfilled in Jesus. In a very real sense the hermeneutical guide to interpreting the Old Testament is the New Testament: the New Testament (as I think it was J.B. Phillips who said) is little more, in one sense, than a pastiche of quotations of the Old Testament. In so emphasizing that he has come to fulfill the Law and the Prophets, not deny or undermine them, at the same time Jesus then exalts the authority and power and reliability of the Bible itself. Not one iota, not one jot or tittle, not one little bit, not one stroke of a pen, is to be taken away from the Bible. Those of us who are familiar with the modern study of historical criticism will wonder what Jesus can mean by this, but what Jesus is talking about both references to the original manuscripts, and also to the approach we are to take to the Bible as a whole. Those who emphasize the authority, the inerrancy, the total truth and trustworthiness of the Bible, will be those who are called great in the kingdom of heaven. Teachers: if you want to be great in the kingdom of heaven, take the Bible seriously.  

Finally, these two sections are joined together with an aphorism, a saying, that starts to reveal the overall purpose of the Sermon of the Mount. We have seen this already from the Beatitudes: their introduction tells how to become a Christian and what it means to live as a Christian. Well, the Sermon on the Mount is not merely a guidebook for Christian living. That is to totally misunderstand its purpose. Certainly, there is guidance here for Christian living, without a doubt. But the Sermon on the Mount is more than that: it is setting the standard so high, the standard that God requires, that we all realize that we must build the house of our lives upon the salvation (upon the “rock”) of Jesus himself.  

So here: our righteousness is not enough unless it exceeds those famously righteous people, the Pharisees. Of course, they, as we know, were often self-righteous, and merely a righteousness of form, not of substance. Well, our righteousness is to be more than that: it is to be a righteousness that is from the inside out, about the motivations of our heart, and not just whether we look religious on the outside. So, next Jesus will teach what it means to have this inner righteousness as he interprets the moral law in a true, biblical, and spiritual way.  

At the end of this section we can ask ourselves two questions. 1) Are we living as moral preservatives, spiritual illuminators? 2) Do we treat the Bible with seriousness and integrity? And as we look at the last sentence of this section, we are prepared to hear what Jesus has to say about true, internal, spiritual righteousness in the next section that we will start to look at tomorrow.


Josh Moody (Ph.D., University of Cambridge) is the senior pastor of College Church in Wheaton, IL., president and founder of God Centered Life Ministries, and author of several books including How the Bible Can Change Your Life and John 1-12 For You.


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