Kingdom Influence: Salt & Light (preaching resource for 2/8/26, Epiphany 5)
This post exegetes Matthew 5:13-16, providing context for the Gospel reading on 2/8/26, the 5th Sunday in the season of Epiphany. Insights are drawn from John Stott's book, “The Message of the Sermon on the Mount” and from Dallas Willard’s book “The Divine Conspiracy.”
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| "Salt and Light" from IStock (with permission) |
Introduction
If the beatitudes (Matt. 5:1-12) describe how citizens of Jesus’ Kingdom participate in and express their Master’s character, the salt and light metaphors indicate how that participation influences the surrounding world. What we’ll learn is that Jesus ‘rubs off’—his personal presence—his life and love—influences for the good.
Having studied the beatitudes, we might be wondering, what lasting good in the world can the poor and the meek do, the mourners and the merciful, and the peacemakers? Would they not simply be overwhelmed by the floodtide of evil? What can they accomplish whose only passion is an appetite for righteousness, and whose only weapon is purity of heart? Are not such people too feeble to achieve anything, especially as a minority in the community?
Understand that Jesus is a realist—he is the ultimate of what is truly ‘real’. But understand this as well—his reality turns this ‘unreal’ world on its head. Jesus’ way is counter-cultural. His kingdom clashes with the kingdoms of this world. But note this as well—his kingdom, his personal presence, always influences the world for good. That is his way. And he invites us to walk with him in it.
Now, Jesus full well knows that the world will persecute the church (Mat. 5:10-12); yet Jesus calls us to join him in his passionate mission of serving and saving the world (Mat. 5:13-16). Incredible as it may sound, Jesus says that a handful of Palestinian peasant disciples in the 1st century, and a handful of comparative nobody’s in this century are the salt of *the earth* and the light of *the world*–so far-reaching was and is their influence to be. Jesus defines that influence using two domestic metaphors. Every home, however poor, used (and still uses today) both salt and light. During his own boyhood, Jesus must often have watched his mother use salt in the kitchen and light the lamps when the sun went down. Salt and light are indispensable household commodities.
The need for light is obvious. Salt, on the other hand, had a variety of uses. It was both a condiment and a preservative. It seems to have been recognized from time immemorial as an essential component of human diet and as a seasoning for food: `Can that which is tasteless be eaten without salt?’ (Job 6:6). In particular, however, in the centuries before refrigeration had been invented, it was used to cure meat in order to prevent decay.
The basic truth which lies behind these two metaphors and is common to them both is that the church and the world are two distinct communities representative of two distinct kingdoms. On the one hand there is `the earth'; on the other there is `you' who are the earth's salt. On the one hand there is `the world'; on the other there is `you' who are the world's light. True, the two communities (`they' and `you') are related to each other, but their relatedness depends on their distinctness.
Further, the metaphors tell us something about both communities. The world is evidently a dark place, with little or no light of its own, since an external source of light is needed to illuminate it. True, the world often talks about its ‘enlightenment', but much of its boasted light is in reality nothing but another form of darkness. The world also manifests a constant tendency to deteriorate. The notion is not that the world is merely tasteless and that Christians can make it more palatable. Rather, the analogy is that the world is putrefying (rotting) and unable to stop itself from going bad. Only salt introduced from outside can do this. Thus Jesus’ presence in the world through the church (the community of Jesus-followers), plays a double role: as salt to arrest - or at least to hinder - the process of social decay; and as light to dispel the darkness.
When we look at these two metaphors more closely, we see that they are deliberately phrased in order to be parallel to each other. In each case Jesus first makes an affirmation (`You are the salt of the earth,' `You are the light of the world'). Then he adds a rider, the condition on which the affirmation depends (the salt must retain its saltiness; the light must be allowed to shine). Salt is good for nothing if its saltiness is lost; light is good for nothing if it is concealed.
1. You are the salt of the earth
Matthew 5:13
The affirmation is straightforward: 'You are the salt of the world' (NEB). This means that, when the world is true to its (fallen) nature, it decays like rotten fish or meat, and when the church is true to its (redeemed) nature, it hinders that decay. Of course God has set other restraining influences in the world. He has himself established certain institutions in his common grace, which curb man's selfish tendencies and prevent society from slipping into anarchy. Chief among these are the state (with its authority to frame and enforce laws as Paul notes in Romans 13) and the home (including marriage and family life). These exert a wholesome influence in the world. Nevertheless, God intends the most powerful influence for good in the world to be the personal presence of Jesus in and through his own redeemed people.
The effectiveness of salt, however, is conditional: if it looses its saltiness it is of no value—not even for the compost heap. In our day refined salt is quite stable and does not cease to be salty. But in first century Palestine what was then popularly called 'salt' was in fact a white powder which, while containing pure salt, also contained much else, since, in those days, there were no refineries. Of this dust the pure salt was probably the most soluble component and so was easily washed out leaving a white powder which still looked like salt, and was doubtless still called salt, but it neither tasted nor acted like salt. It was just road dust.
So too a Christian: 'Have salt in yourselves,' Jesus said on another occasion (Mk. 9:50). Christian saltiness is Christian character as depicted in the beatitudes, committed Christian discipleship exemplified in both deed and word (Lk. 14:34, 35; Col. 4:6). For effectiveness the Christian must retain his Christ-likeness, as salt must retain its saltiness. If Christians embrace worldly values and display sinful behaviors, they become contaminated by the impurities of the world and thus lose their influence for good in the world. The influence of Christians in and on society depends on their being distinct, not identical. If we Christians are indistinguishable from non-Christians, we are ineffective in sharing Jesus’ life and love with others. We might as well be discarded like saltless salt, 'thrown out and trodden underfoot by men.'
2. You are the light of the world
Matthew 5:14-16
Jesus introduces the second metaphor with a similar affirmation: *You are the light of the world*. True, he was later to say 'I am the light of the world' (Jn. 8:12; 9:5). And so our light is derivative—it is from the Lord, reflective of his glory, making us, in Christ, like stars in the night sky (cf. Phil. 2:15). This light, says Jesus, is manifested to the world in and through our 'good works'. When others see these good works, he said, they will *give glory to your Father who is in heaven*.
What are these ‘good works’? It seems that the expression covers everything a Christian says and does that reflects the ‘light’—the life and love of Jesus into a dark and dying world. Good works are the visible expression of Jesus. This would, of course, include deeds of compassion—for these embody the good news of the presence of Jesus’ Kingdom. But it also includes our words of testimony concerning the truth and joy of Jesus’ Kingdom presence.
In the Bible, light is a common symbol of truth, and thus a Christian's shining light must surely include the spoken testimony concerning Jesus who is the Truth. The Old Testament prophesy that God's Servant would be 'a light to the nations' is said to have been fulfilled not only in Christ himself, the light of the world, but also by Christians who bear witness to Christ (Is. 42:6; 49:6; Lk. 2:32; Acts 26:23; 13:47). Evangelism must be counted as one of the 'good works' by which our light shines and our Father is glorified.
As with the salt so with the light, the affirmation is followed by a condition: *Let your light ... shine before men.* If salt can lose its saltiness, the light in us can become darkness (Mat. 6:23). We must allow the light of Christ within us to shine out from us, so that people may see it. We are not to be like a town or a village nestling in a valley whose lights are concealed from view, but like *a city set on a hill*, which *cannot be hid* and whose lights are clearly seen for miles around. Again, we are to be like a lighted lamp, 'a burning and shining lamp' as John the Baptist was (Jn. 5:35) which is set on a lampstand in a prominent position in the house so that *it gives light to all in the house*, and is not stuck 'under the meal-tub' (NEB) or 'under a bucket' (JBP), where it can do no good.
Our calling is to be true to who Christ in us really is—we are to be our true Christian selves, openly living the life described in the beatitudes, and not ashamed of Christ. Then people will see us and our good works, and seeing us will glorify God. For they will inevitably recognize that it is by the grace of God we are what we are, that *our* light is really *his* light, and that our works are his works done in us and through us. So it is the light they will praise, not the lamp which bears it; it is our Father in heaven whom they will glorify, not the children he has begotten and who exhibit a certain family likeness. Even those who revile us may not be able to help glorifying God for the very righteousness on account of which they persecute us (Mat. 5:10-12).
3. Lessons about salt and light
Jesus’ teaching about salt and light has much to teach us about our Christian responsibilities in the world. Three lessons are prominent.
a). There is a fundamental difference between Christians and non-Christians.
It is certainly true that some non-Christians live in ways that conform to certain Christian values. It’s also true that some professing Christians live in ways that are indistinguishable from non-Christians. Yet the essential difference remains. Jesus said that they are as different as light from darkness, as different as salt from decay and disease. We serve neither God, nor ourselves, nor the world by attempting to obliterate or even minimize this difference.
This theme is basic to the Sermon on the Mount. The Sermon is built on the assumption that Christians *are* different, and it issues a call to us to *be* different. Probably the greatest tragedy of the church through its long and checkered history has been its constant tendency to conform to the prevailing culture instead of developing a Christian counter-culture that fully expresses Jesus’ Kingdom reign.
b). We must accept the responsibility which this distinction puts upon us.
It is when in each metaphor we bring the affirmation and the condition together that our responsibility stands out. Each affirmation begins in the Greek sentence with the emphatic pronoun 'you', as much as to say 'you and only you' are the earth's salt and the world's light. And *therefore* - the condition follows with inexorable logic - you simply must not fail the world you are called to serve. You must be what you are. You are salt so you must retain your saltiness and not lose your Christian tang. You are light, and you must let your light shine and not conceal it in any way, whether by sin or by compromise, by laziness or by fear.
This call to assume our Christian responsibility, because of what God has made us and where he has put us, is particularly relevant in a quickly moving, high-tech world where we can seem so small, so feeble, so ineffective. What can we do to have any sort of impact in such a world? We can participate in a counter-cultural revolution. We can rise above feelings of alienation and helplessness and be dedicated activists who join Jesus in advancing a revolution of love, joy and peace that changes both institutions and individuals.
Sound too lofty or too good to be true? Have we lost our confidence in the power of the gospel of Christ? Jesus is all the salt and light this dark and decaying world needs. But we must have salt in ourselves, and we must let our light shine.
c). We must see our Christian responsibility as twofold.
'Salt and light have one thing in common: they give and expend themselves - and thus are the opposite of any and every kind of self-centered religiosity. Nevertheless, the kind of service each renders is different. In fact, their effects are complementary. The function of salt is largely negative: it prevents decay. The function of light is positive: it illumines the darkness. Thus Jesus calls upon us as his disciples to exert a double influence on the secular community, a negative influence by arresting its decay and a positive influence by bringing light into its darkness. For it is one thing to stop the spread of evil; it is another to promote the spread of truth, beauty and goodness.
Putting the two metaphors together, it seems legitimate to discern in them the proper relation between social action and evangelism in the total mission of Christ in the world. Take first our vocation to be salt. The apostle Paul paints a grim picture at the end of the first chapter of his Roman letter of what happens when society suppresses (out of love for evil) the truth it knows by nature. It deteriorates. Its values and standards steadily decline until it becomes utterly corrupt. God sets Christians within such societies to hinder the decay. God intends us to penetrate the world as preserving agents. Christian salt has no business to remain snugly in elegant little ecclesiastical salt cellars; our place is to be rubbed into the secular community, as salt is rubbed into meat, to stop it going bad. Sadly, it seems that as societies decay, many Christians throw up their hands in pious horror and reproach the non-Christian world; but should we not rather reproach ourselves? One can hardly blame unsalted meat from going bad. It cannot do anything else. The real question to ask is; where is the salt?
Christian salt accomplishes its preserving effect through both deeds and words. We have already seen that God has created both the state and family as social structures to restrain evil and encourage goodness. And Christians have a responsibility to see that these structures are strengthened and operate with justice. However small our part may be, we cannot opt out of seeking to support and strengthen these structures for good. Whenever Christians are conscientious citizens, they are acting like salt in the community.
But understand this, the reformation of society’s institutions, no matter how important, is not enough. Fallen human beings need more than barricades to stop them becoming as bad as they could be. They need regeneration, new life through the gospel. Hence our second vocation to be 'the light of the world'. For the truth of the gospel is the light, contained indeed in fragile earthenware lamps, yet shining through our earthenness out to the world. We are called both to spread the gospel and to frame our manner of life in a way accurately communicates the gospel. (cf. Phil. 1:27).
Conclusion
As Christ-followers we are to be both salt and light. The world, which Jesus loves and saves, needs both from us. The world is in decay unto death and needs salt; and it is in utter darkness and needs light. Our Christian vocation is to be both. As we embrace Jesus and his life and love, we then allow Jesus to be expressed through us out to others. In doing so, we fulfill our calling to the world both for the world’s benefit and for Christ’s glory.