The Point: Make your influence count for what matters.
A Christian’s Influence: Matthew 5:13-16.
 "You are the salt of the earth, but if salt has lost its taste, how shall its saltiness be restored? It is no longer good for anything except to be thrown out and trampled under people’s feet.  "You are the light of the world. A city set on a hill cannot be hidden.  Nor do people light a lamp and put it under a basket, but on a stand, and it gives light to all in the house.  In the same way, let your light shine before others, so that they may see your good works and give glory to your Father who is in heaven. [ESV]
“If the beatitudes describe the essential character of the disciples of Jesus, the salt and light metaphors indicate their influence for good in the world. Yet the very notion that Christians can exert a healthy influence in the world should bring us up with a start. What possible influence could the people described in the beatitudes exert in this hard, tough world? What lasting good can the poor and the meek do, the mourners and the merciful, and those who try to make peace not war? 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 if they are a small minority in the world? It is evident that Jesus did not share this skepticism. Rather the reverse. The world will undoubtedly persecute the church [10-12]; yet it is the church’s calling to serve this persecuting world [13-16]. Incredible as it may sound, Jesus referred to that handful of Palestinian peasants as the salt of the earth and the light of the world, so far reaching was their influence to be. In order to define the nature of their influence, Jesus resorted to two domestic metaphors. Every home, however poor, used and still uses both salt and light. Salt and light are indispensable household commodities. The basic truth which lies behind these metaphors and is common to them both is that the church and the world are distinct communities: you … they, salt … earth, light … world. True, the two communities are related to each other, but their relatedness depends on their distinctness. It is important to assert this clearly in our day in which it is theologically fashionable to blur the distinction between the church and the world, and to refer to all mankind indiscriminately as ‘the people of God’. 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 illumine it. The world also manifests a constant tendency to deteriorate. The notion is not that the world is tasteless and that Christians can make it less insipid, but that it is putrefying. It cannot stop itself from going bad. Only salt introduced from outside can do this. The church, on the other hand, is set in the world with 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 the 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. Then He adds a rider, the condition on which the affirmation depends. Salt is good for nothing if its saltness is lost; light is good for nothing if it is concealed.
1. The salt of the earth . This means that, when each community is itself and is true to itself, the world decays like rotten fish or meat, while the church can hinder its decay. Of course God has set other restraining influences in the community. 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 and the home. Nevertheless, God intends the most powerful of all restraints within sinful society to be His own redeemed, regenerate and righteous people. The effectiveness of salt, however, is conditional: it must retain its saltness. Christian saltness is Christian character as exemplified in both deed and word. For effectiveness the Christian must retain his Christlikeness, as salt must retain its saltness. If Christians become assimilated to non-Christians and contaminated by the impurities of the world, they lose their influence. The influence of Christians in and on society depends on their being distinct, not identical.
2. The light of the world [14-16]. Jesus introduces His 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 [John 8:12; 9:5]. But by derivation we are too, shining with the light of Christ, shining in the world like stars in the night sky. What this light is Jesus clarifies as our good works . Let men once see your good works, He said, and they will give glory to your Father who is in heaven, for it is by such good works that our light is to shine. It seems that good works is a general expression to cover everything a Christian says and does because he is a Christian, every outward and visible manifestation of his Christian faith. Since light is a common biblical symbol of truth, a Christian’s shining light must surely include his spoken testimony. Evangelism must be counted as one of the good works by which our light shines and our Father is glorified. Good works are works of love as well as of faith. They express not only our loyalty to God, but our care for our fellows as well. Indeed, the primary meaning of works must be practical, visible deeds of compassion. It is when people see these, Jesus said, that they will glorify God, for they embody the good news of His love which we proclaim. Without them our gospel loses its credibility and our God His honor. As with the salt, so with the light, the affirmation is followed by a condition: let your light shine before others. If salt can lose its saltness, the light in us can become darkness [6:23]. But we are to allow the light of Christ within us to shine out from us, so that people may see it. That is, as the disciples of Jesus, we are not to conceal the truth we know or the truth of what we are, but be willing for our Christianity to be visible to all. 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 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 [10-12].
3. Lessons to learn. The salt and light metaphors which Jesus used have 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, between the church and the world. 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 throughout its long and checkered history has been its constant tendency to conform to the prevailing culture instead of developing a Christian counter-culture. 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. This call to assume our Christian responsibility, because of what God has made us and where He has put us, is particularly relevant to young people who feel frustrated in the modern world. We are not helpless and powerless. For we have Jesus Christ, His gospel, ideals and power, and Jesus Christ is all the salt and light this dark and rotten 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. So Jesus calls 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. What does it mean in practice to be the salt of the earth? To begin with, we Christian people should be more courageous, more outspoken in condemning evil. Condemnation is negative, to be sure, but the action of salt is negative. The real salt is the true exposition of Scripture, which denounces the whole world and lets nothing stand but the simple faith in Christ. Salt bites, and the unadulterated message of the judgment and grace of God has always been a biting thing. And alongside this condemnation of what is false and evil, we should take our stand boldly for what is true, good and decent. Christian salt takes effect by deeds as well as words. But 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 very earthenness with the more conspicuous brightness. We are called both to spread the gospel and to frame our manner of life in a way that is worthy of the gospel. So then, we should never put our two vocations to be salt and light, our Christian social and evangelistic responsibilities, over against each other as if we had to choose between them. We should not exaggerate either, nor disparage either, at the expense of the other. Neither can be a substitute for the other. The world needs both. It is bad and needs salt; it is dark and needs light. Our Christian vocation is to be both.” [Stott, pp. 57-68].
A Christian’s Righteousness: Matthew 5:17-20.
 "Do not think that I have come to abolish the Law or the Prophets; I have not come to abolish them but to fulfill them.  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.  Therefore whoever relaxes one of the least of these commandments and teaches others to do the same will be called least in the kingdom of heaven, but whoever does them and teaches them will be called great in the kingdom of heaven.  For I tell you, unless your righteousness exceeds that of the scribes and Pharisees, you will never enter the kingdom of heaven. [ESV]
“So far Jesus has spoken of a Christian’s character, and of the influence he will have in the world if he exhibits this character and if his character bears fruit in good works. He now proceeds to define further this character and these good works in terms of righteousness. He explains that the righteousness He has already mentioned twice as that for which His disciples hunger  and on account of which they suffer  is a conformity to God’s moral law and yet surpasses the righteousness of the scribes and Pharisees . The good works are works of obedience. He began His Sermon with beatitudes in the third person; He continued in the second person; and now He changes to the authoritative first person and uses for the first time His distinctive and dogmatic formula I say to you or I tell you. This paragraph is of great importance not only for its definition of Christian righteousness but also for the light it throws on the relation between the New Testament and the Old Testament, between the gospel and the law. It divides itself into two parts, first Christ and the law [17-18] and secondly the Christian and the law [19-20].
1. Christ and the law [17-18]. Jesus begins by telling them not for one moment to imagine that He had come to abolish the Law or the Prophets, i.e. the whole Old Testament or any part of it. Certainly from the very beginning of His ministry, people had been struck by His authority. It was natural therefore that many were asking what the relation was between His authority and the authority of the law of Moses. It was clear to them that the scribes were submissive to it, for they were ‘teachers of the law’. They devoted themselves to its interpretation and claimed for themselves no authority apart from the authorities they quoted. But it was not so clear with Jesus. Jesus spoke with His own authority. What was this authority of His? Was He setting Himself up as an authority over against the sacred law, the word of God? It was this question that Jesus answered in verse 17. He had come neither to abolish the law and the prophets, setting them aside or abrogating them, nor even just to endorse them in a dead and literalistic way, but to fulfill them. In order to grasp the far-reaching implications of this, we need to recall that the Old Testament contains various kinds of teaching. First, the Old Testament contains doctrinal teaching. All the great biblical doctrines are there, but only a partial revelation. Jesus fulfilled it all in the sense of bringing it to completion by His person, His teaching and His work. Second, the Old Testament contains predictive prophecy. Much of it looks forward to the days of the Messiah, and either foretells Him in word or foreshadows Him in type. Yet this was only anticipation. Jesus fulfilled it all in the sense that what was predicted came to pass in Him. Again and again Jesus claimed that the Scriptures bore witness to Him. The climax was His death on the cross in which the whole ceremonial system of the Old Testament, both priesthood and sacrifice, found its perfect fulfilment. Third, the Old Testament contains ethical precepts, or the moral law of God. Yet they were often misunderstood and even more often disobeyed. Jesus fulfilled them in the first instance by obeying them. He does more than obey them Himself; He explains what obedience will involve for His disciples. He rejects the superficial interpretation of the law given by the scribes; He Himself supplies the true interpretation. His purpose is not to change the law, still less to annul it, but to reveal the full depth of meaning that it was intended to hold. So then He fulfills it by declaring the radical demands of the righteousness of God. This is what He stresses in the rest of Matthew 5 by giving examples. Thus the attitude of Jesus to the Old Testament was not one of destruction and of discontinuity, but rather of a constructive, organic continuity. Having stated that His purpose in coming was to fulfill the law, Jesus went on to give the cause and the consequence of this. The cause is the permanence of the law until it is fulfilled , and the consequence is the obedience to the law which the citizens of God’s kingdom must give [19-20]. This is what Jesus has to say about the law He has come to fulfill: 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 . None of the Old Testament will pass away or be discarded, He says, not a single letter or part of a letter, until it has all been fulfilled. And this fulfilment will not be complete until the heaven and the earth themselves pass away. Thus the law is as enduring as the universe. The final fulfilment of the one and the new birth of the other will coincide. Both will pass away together. Jesus could not have stated more clearly than this His own view of Old Testament Scripture.
2. The Christian and the law [19-20]. The word therefore introduces the deduction which Jesus now draws for His disciples from the enduring validity of the law and His own attitude with respect to it. It reveals a vital connection between the law of God and the kingdom of God. Because He has come not to abolish but to fulfil, and because not an iota or dot will pass from the law until all has been fulfilled, therefore greatness in the kingdom of God will be measured by conformity to it. Nor is personal obedience enough; Christian disciples must also teach to others the permanently binding nature of the law’s commandments. Even one of the least of these commandments, precisely because it is a commandment of God the King, is important. To relax it – i.e. to loosen its hold on our conscience and its authority in our life – is an offense to God whose law it is. To disregard a least commandment in the law (in either obedience or instruction) is to demote oneself into a least subject in the kingdom; greatness in the kingdom belongs to those who are faithful in doing and teaching the whole moral law. Jesus now goes further still. Not only is greatness in the kingdom assessed by a righteousness which conforms to the law, but entry into the kingdom is impossible without a conformity better than that of the scribes and Pharisees, for God’s kingdom is a kingdom of righteousness. Christian righteousness far surpasses pharisaic righteousness in kind rather than in degree. Christian righteousness is greater than pharisaic righteousness because it is deeper, being a righteousness of the heart. Pharisees were content with an external and formal obedience, a rigid conformity to the letter of the law; Jesus teaches us that God’s demands are far more radical than this. The righteousness which is pleasing to Him is an inward righteousness of mind and motive. This deep obedience which is a righteousness of the heart is only possible in those whom the Holy Spirit has regenerated and now indwells. This is why entry into God’s kingdom is impossible without a righteousness greater than that of the Pharisees. It is because such a righteousness is evidence of the new birth, and no one enters the kingdom without being born again.” [Stott, pp. 69-81].
Questions for Discussion:
1. What is Jesus teaching us with the two metaphors: salt and light? What does it mean for a Christian to be salt and light to the world? How can you be salt and light in your everyday life?
2. What lessons do we learn from Jesus’ use of the metaphors: salt and light?
3. Define righteousness as Jesus uses the term in 5:17-20. What does Jesus teach us in these verses concerning the relationship between the Old and New Testaments; between the law and the gospel? How can your personal righteousness be greater than the scribes and Pharisees?
Matthew, volume 1, James Boice, Baker.
Jesus’ Sermon on the Mount, D. A. Carson, Global Christian Publishers.
The Sermon on the Mount, Sinclair Ferguson, Banner of Truth.
The Gospel According to Matthew, Leon Morris, Eerdmans.
The Message of the Sermon on the Mount, John Stott, Inter Varsity.