Salt and Light: The Sermon on the Mount

Lesson 3: Salt and Light (Mt 5:13-16)

The Sermon on the Mount

Part 1: The Subjects of the Kingdom (Mt 5:3-16)

The Distinctiveness of the Disciples:

Citizens of the Kingdom Have a Positive Influence

Jesus’ focus in the Beatitudes was primarily on interior, personal characteristics such as dependency, meekness, yearning for righteousness, mercifulness, authenticity, and purity. These personal traits are private, yet have public implications. Those displaying such characteristics will be noticeable. Thus, Jesus now shifts the emphasis to the external, public characteristics of citizens of His kingdom.

The poetic nature of Jesus’ sermon is clearly evident here. His statements “Ye are the salt of the earth” and “Ye are the light of the world” are obviously metaphorical expressions designed to highlight a comparison. Subjects of the kingdom are in some ways like salt and like light. Those who are not “salty” and those whose lights do not shine forth in the world are failing to live up to divine expectations. Thus, the passage serves as a warning to flavorless and unnoticeable believers.

  1. “Ye are the salt of the earth.”

    1. The significance of salt:

      1. Preservative—salt delays decay and retards deterioration; it’s an antiseptic. Without refrigeration, salting down food products was the best way to preserve them.1 The preservative quality of salt is likely Jesus’ primary idea here.

      2. Flavor enhancer—salt adds flavor.

      3. Other ideas associated with salt: the rabbis apparently used salt as a symbol of wisdom; whiteness; pungency; thirst-producing. OT meat offerings were always to be seasoned with the “salt of the covenant” (Lev 2:13).

    2. The comparison: citizens of the kingdom should have an influence in their world. They should suppress or halt moral decay and they should enhance the “flavor” of the culture. The presence of believers should restrain evil in the world.

“The world tends toward decomposition and is actually rotting away. When the world is left to itself, it festers and putrefies, for the germs of evil are everywhere present and active. … We live in a world that constantly tends toward decay. Some of the Christless structures of the world may look okay, but inside they are rotting away, and it is just a matter of time before they fall. … This suggests to us the function of the church: The church, as salt, functions as a retardant to decay and a preservative in a disintegrating world.”2

    1. A potential condition: the salt “have lost its savor.” The Greek word literally means “to become foolish,” but in this case means “to lose taste, to become inert.” I.e., the salt loses its capacity to do its job. Jesus seems to be talking about believers who lose their influence in the world. They become inert, “tasteless,” and inoffensive. Salt-less Christians are bland and tasteless, adding nothing to the community and doing nothing to stop moral decay. They may be practically indistinguishable from the surrounding culture. The secular world has a bigger affect on Christians than Christians have on the world. Examples: how are we different from the world when it comes to materialism? morality? honesty? compassion? entertainment?

    2. What kind of a world would we live in without Christian influence? Imagine how much worse condition the world would be in without the positive contributions and the restraining influence of Christianity.

    3. Salt has little or no effect if it is not applied to some other material. Salty believers must exert their influence throughout society in order for them to do any good. They must get “out of the salt shaker.” Christian isolationism is not biblical.

    4. A potential problem: Salt generally does not lose its saltiness; it does not become inert. Chemically speaking, salt is salt. It doesn’t break down unless it is impure or chemically changed.3 So it seems that Jesus is setting forth an impossible condition. Yet this sort of language is not foreign to Jesus’ teachings (e.g., a camel cannot go through the eye of a needle [Mt 19:24]). The statement is ironic or paradoxical—it doesn’t make sense on the face of it, which makes it memorable and causes the hearer or reader to pause and consider the statement more closely. “How absurd—salt losing its saltiness!” Thus, the hearers or readers should realize that, as salt, citizens of the kingdom should not lose their “savor,” that is, their influence in the world. Like salt, they cannot become un-salty. Such a notion is absurd.

    5. A potential result:

      1. Good for nothing—failing to fulfill their purpose, failing to live up to their responsibilities.

      2. To be cast out and trodden under foot—unwanted salt would commonly be thrown on to paths or roadways.

    6. The application:

      1. Beware lest you lose the distinctive Christian “flavor” and become just like the unsaved crowd. Christians who are the same as everyone else are in a sense “good for nothing” and worthy of chastisement. They are not distinctive and have little positive influence. They go along with the crowd and never restrain sin.

      2. Israel was the perfect example of salt that had lost its savor and was good for nothing, being cast out and trodden under foot (cf. Mt 8:12).

      3. The Christian church today, generally speaking, has lost much of its saltiness. Many segments of Christianity, especially in free and prosperous countries, believers are so worldly that they have few distinguishing marks separating them from non-Christians. The influence of the church on the western world is slowly fading. Thankfully, in many parts of the world, Christianity is having a remarkable impact.

Rev 3:16 So then because thou art lukewarm, and neither cold nor hot, I will spue thee out of my mouth.

    1. Jesus is not implying that an un-salty believer may lose his salvation. This is a warning, not a threat. Further, remember that in wisdom literature you can’t press the literal meaning of the words too far. Focus on the main point of the comparison, not on every little detail and nuance.

    2. The main point of the comparison: retain your gospel witness and testimony in the world; be a good example to others; have an impact on society; be different (in a good sense); seek to retard moral decay; seek to be a positive influence.

  1. “Ye are the light of the world.”

    1. Significance of light: illumination, dispels the darkness, show the way, reveal the truth, etc. While salt has a negative function (preventing decay), light has a positive function (showing the way).

    2. God is light (1 Jn 1:5) and Jesus is “the true Light, which lighteth every man that cometh into the world.”(John 1:9). Jesus called himself “the light of the world” (John 8:12, 9:5), so it’s remarkable that he says of his disciples, “You are the light of the world.” In contrast, the world is a dark place. The people of the world “sit in darkness” (Luke 1:79), and “men love darkness rather than light because their deeds are evil” (John 3:19).

Light is a common symbol in the Bible. It represents purity, truth, knowledge, divine revelation, and God’s presence all in contrast to their opposites. The Israelites thought of themselves as lights in a dark world (Isa. 42:6; Rom. 2:19). However the Old Testament spoke of Messiah as the true light of the world (Isa. 42:6; 49:6). Jesus’ disciples are lights in the derived sense, as the moon is a light but only because it reflects the light of the sun.4

    1. Point of comparison: a light is visible, obvious, and noticeable; it shines forth. Citizens of the kingdom are “the light of the world.” They must be obvious, visible, and noticeable. There can be no such thing as a secret or invisible Christian.

    2. Positive examples

      1. A city situated on a hilltop cannot be hid; it is visible, obvious, clearly seen from a long distance, especially at night.

      1. A lamp5 on a lampstand gives light to all in the house.

    1. A negative example: a lamp put under a “bushel” (a clay container for dry foods, usually a bowl or vase, holding about two gallons). This is patently obvious—so absurd that it never happens. A lamp is to be displayed on a lampstand6 so that it may shine forth its light.

    2. The command: “let your light so shine before men.” Those who possess the light must transmit or shine the light. What a lamp is in a room, disciples of Christ are to be in the world. Followers of Christ are both visible and radiant.

[Believers] are the light lighted. He is the sun. They resemble the moon, reflecting the sun’s light. Apart from Christ they cannot shine. The electric bulb does not emit light all by itself. It imparts light only when connected and turned on, so that the electric current generated in the power-house is transmitted to it. So also as long as Christ’s followers remain in living contact with the original light they are a light to others (cf. John 15:4, 5).7

    1. The results:

      1. People see your good works.

        1. The assumption is that citizens of Jesus’ kingdom are doing good works. He doesn’t specify what kind of good works, other than the kind that others might observe.

        2. Jesus later tells us not do religious works (charity, prayer, fasting) before men, to be seen of them (see Mt 6:1, 5, 16). One should not do good works to gain personal prestige or status but to be a good testimony. So one’s Christian testimony should be plainly visible, but one’s private religious duties should be done very quietly.

      2. People glorify God. This is no guarantee that unbelievers will turn to God based on your good works, but it does suggest that the believer’s good works may be helpful in leading others to Christ. Read Ephesians 5:8-9 and Philippians 2:15.

Tertullian (c. a.d. 200) wrote: “But it is mainly the deeds of a love so noble that lead many to put a brand upon us. ‘See,’ they say, ‘how they [the Christians] love one another,’ for they themselves [the non-Christians] are animated by mutual hatred; ‘see how they are ready even to die for one another’” (Apology XXXIX).8

“Brighten the corner where you are.”

Conclusion: Let’s commit ourselves to being salt and light in our community. As salt, we want to be a force against moral decay and a source of “flavor” to our world. As light, we must shine forth brightly in a dark world with the gospel message and with a positive Christian testimony.

1 Interesting note: the body of the great missionary David Livingstone was shipped from Africa back to England after his death packed in salt.

2R. Kent Hughes, The Sermon on the Mount, 78.

3 Some have suggested that the salt of that time was often impure, and in certain conditions the salt itself would leach away, leaving a worthless residue. This may be true, but seems overly complicated for the analogy.

4Tom Constable, Tom Constable’s Expository Notes on the Bible (Galaxie Software, 2003; 2003), Mt 5:14.

5 The word “candle” (KJV) refers to the small, portable lamp, a clay vessel burning olive oil, not a wax candle.

6 A lampstand might be a shelf extending from the pillar in the center of the room (the pillar that supported the large crossbeam of the flat roof), or a single stone projecting inward from the wall, or a piece of metal conspicuously placed and used similarly. Many houses of this time were usually rather simple, having only one or two rooms, so one lamp could illuminate the whole building. William Hendriksen and Simon J. Kistemaker, vol. 9, New Testament Commentary.

7William Hendriksen and Simon J. Kistemaker, vol. 9, New Testament Commentary.

8Quoted in William Hendriksen and Simon J. Kistemaker, vol. 9, New Testament Commentary.


  1. Thanks! Very useful!

  2. lot of deep thought. thanks so much

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