13"You are the salt of the earth. But if the salt loses its saltiness, how can it be made salty again? It is no longer good for anything, except to be thrown out and trampled by men.
14"You are the light of the world. A city on a hill cannot be hidden. 15Neither do people light a lamp and put it under a bowl. Instead they put it on its stand, and it gives light to everyone in the house. 16In the same way, let your light shine before men, that they may see your good deeds and praise your Father in heaven."
In the previous verses of His Sermon on the Mount, Jesus spoke of the blessedness of His true disciples in the passage known as "the Beatitudes". As He continues, Jesus now begins speaking of our responsibility as His disciples: "You are the salt of the earth" (vs. 13). To understand this statement, we must reflect upon the attributes of "salt": salt preserves from corruption; salt seasons; salt produces thirst. Let's look at each of these. First, salt preserves from corruption. Salt can be used to slow the spoilage of food. So we also have been called as disciples of Christ to preserve the earth from corruption. We must have a positive moral influence upon the earth, so that (by our presence) society is preserved from corruption--so that the moral decay of society is slowed. We can, by our godly influence, preserve from corruption the moral climate of our immedieate environment. For instance, if it is known in our work place that we do not tolerate the cursing of God's name, and then if (thereby) our co-workers are less apt to curse God's name, we have then by our influence "preserved from corruption" (to some extent) our work place by setting the moral standard that the cursing of God's name will not be tolerated there. Second, salt seasons. Salt makes food taste better. So also, we as Christ's disciples must make the earth (in a sense) taste better. In other words, we must make the earth a better place to live, primarily by showing the earth the love of God. Salt imparts its seasoning to everything it comes in contact with. When you taste food, you can tell right away if it has been salted. So also, our influence should be evident. The love of God should overflow from our lives, seasoning all those whom we come in contact with. Third, salt produces thirst. So, we as Christ's disciples are to produce thirst in those we come in contact with. Thirst for what? Jesus has just said: "Blessed are those who hunger and thirst for righteousness" (Matt. 5:6). And so, our lives lived for righteousness should cause a thirst for righteousness in those who observe us. People should look at the godliness of our lives and see the love of God flowing through our lives. They should then think, "I want that. I thirst for that life." Our goal should be to have such an influence on others.
Now, Jesus' statement to us is emphatic: "You are the salt of the earth." He is speaking directly to us, His disciples, in a form even stronger than a command. You see, Jesus does not say, "You should be the salt of the earth," or even, "Thou shalt be the salt of the earth." He says, "You are the salt of the earth." In other words, we have no choice in the matter. This is not a command that we carry out; rather, it is an unchangeable attribute of a disciple of Christ that we are the salt of the earth. Now, sadly, many of us do not perform well our role as "the salt of the earth". Thus Jesus warns: "But if the salt loses its saltiness, how can it be made salty again? It is no longer good for anything, except to be thrown out and trampled by men" (vs. 13). And so, if we as disciples of Christ fail to have a godly influence upon society, we are worthless as disciples of Christ, "no longer good for anything, except to be thrown out and trampled by men." We have seen this happen time and time again. A prominent Christian will be caught in gross sin, thereby "losing [his] saltiness". After that, he is "no longer good for anything", and the world certainly takes advantage of the opportunity make sure he is "trampled by men". After such a failure, the disciple of Christ can never be "salt" again; he is ever after seen as a hypocrite. A blown witness can never be recovered.
Jesus enumerates a second characteristic of His disciples: "You are the light of the world" (vs. 14). The disciples of Jesus are "light" in two ways: they are a spiritual "light", showing men the way to God; they are a moral "light", showing men how they ought to live righteously. Jesus enumerates these two aspects of "light" when He says: "[L]et your light shine before men, that they may see your good deeds and praise your Father in heaven" (vs. 16). By saying, "You are the light of the world", Jesus is implying that, despite its claims of enlightenment, the world would be in utter darkness if the light of Christ's disciples were removed.
Now, elsewhere, Jesus says of Himself: "I am the light of the world. Whoever follows me will never walk in darkness, but will have the light of life" (John 8:12). Then, Paul teaches: "For you were once darkness, but now you are light in the Lord" (Eph. 5:8). And so, we as "light" are to be a reflection of the primary source of "light", which is Jesus Christ. The world, now that Jesus has risen to glory, sees the light of Christ primarily through our actions and behavior. Most of the world does not take the time to study God's Word, so they infer what it means to be a Christian by looking at our lives.
Again, just as we have no choice but to be "salt of the earth", so also we have no choice but to be "light of the world". Jesus says: "You are the light of the world", and then, "A city on a hill cannot be hidden" (vs. 14). Once we are identified as a disciple of Christ, we cannot escape observation by the world (which is in darkness). Just as on a dark night, one's eyes naturally are drawn to whatever light is visible; so also, the eyes of those who reside in the darkness of the world are naturally drawn to us as the "light of the world".
Jesus teaches that we should not try to escape the important responsibility of being "the light of the world": "Neither do people light a lamp and put it under a bowl. Instead they put it on its stand, and it gives light to everyone in the house" (vs. 15). Many Christians go out of their way to hide their Christianity. Just as it would be absurd (a waste of time and energy) to "light a lamp and put it under a bowl", so it is absurd (and a waste) for us to try to hide the light of Christ that shines through us. To do so is contrary to the command of Jesus to "let your light shine before men" (vs. 16). Jesus does not want any "secret agents"! Jesus here is speaking also against monasticism. We are not as Christians to hide ourselves from the world in a monastery. This would be akin to putting our lamp "under a bowl". We should consider it an honor to be appointed by Christ to be "the light of the world", and to shine our "light".
Jesus sums it up: "In the same way, let your light shine before men, that they may see your good deeds and praise your Father in heaven" (vs. 16). This is the essence of our "light"hood. Jesus states the method ("they may see your good deeds") and the result ("they may... praise your Father in heaven"). The primary method we are to use in being a "light" is to set a good example, so that others "may see [our] good deeds". While preaching is good, Christianity is primarily exemplary. People respond to our example of service more than anything. Mother Teresa has done more for Christianity than the most knowledgeable of Theological scholars. "Men will not be saved by abstract truth, but by truth embodied."6 "Of all modes of inculcating Christianity, exemplifying it is the best. The best commentary on the Bible the world has ever seen is a holy life. The most eloquent sermon in behalf of the gospel that the world has ever heard is a uniform, active piety. The best version of the written truth that has ever been made is a consistent religious example. The Christian whose light thus shines not only correctly renders, but beautifies the sacred text."[7]
Finally, the primary result of our "light"hood is to glorify God, that those who see our light would "praise your Father in heaven". Many do their good deeds, not to glorify God, but to be esteemed by men. Jesus speaks against this in detail later in His sermon (see Matt. 6), and so we will speak much more of this later. Suffice it to say now that no matter how beneficial our service is to the world, it fails if the result is our own glorification at the expense of God's glory.
Let us close by noting the all-inclusiveness of our roles as "salt" and "light". We are "the salt of the earth" and "the light of the world". The earth and world has no other "salt" and "light" but us, and so our duty to be "salt" and "light" is crucial. Also, note that "salt" operates from within whatever it is in contact with, and "light" operates externally to what it illuminates. Both the near and far are covered. Our influence is to be worldwide.