*Ye* are the salt of the earth; but if the salt have become insipid, wherewith shall it be salted? It is no longer fit for anything but to be cast out and to be trodden under foot by men.
The Lord has just described the character and the blessings of those who belong to His kingdom. Now He turns from what they are inside to what they are in the world around them. Calling them salt raises two questions. What does salt do? And what happens to people who carry the name without the reality?
Salt is not a sweetener. One writer describes what salt does — it guards, and it holds firm what is good:
Salt is what preserves in righteousness. It is sharp rather than sweet, but it guards from impurity and decay. It holds steady what is good and wholesome. It tests all things, and holds fast the right. It keeps away from every form of wickedness. So when the disciples are called the salt of the earth, the Lord marks them out as set apart to God the Father.
God gave an instruction about the offerings brought to Him. Salt was never to be missing:
In ancient times salt was the main way to season food and keep it from going bad. Salt is sharp and bitter, but it keeps what is good and prevents decay. In the Old Testament, the "salt of the covenant" had, by God's order, to be added to all sacrifices (Lev. 2:13). So salt is a clear symbol of the sanctifying, keeping power of God which should show in us. We are not sugar or honey, but the salt of the earth.
One writer draws a line between "the earth" here and "the world" in the next verse:
The salt of the earth is a different thing from the light of the world. As I see it, the earth means what already claimed to have received light from God. Because of that light it stood in a relationship with Him, and had taken a definite shape before Him. The disciples of Christ were the preservative principle in the earth. They were the light of the world, and the world did not have that light.
Kelly brings the same word into the present, to Christendom — the lands where the Christian faith has long been known. He points out where the danger lies, because the light was once there:
The salt of the earth is how the disciples stand toward what already had God's testimony... If you speak about the earth now, it is Christendom — the place that has the light of God's truth, either truly or only in name... And this is the place where the greatest falling away from God will come. Such evil is only possible where people have had the light and then left it.
Commentators differ on who exactly is in view. Some say the verse speaks of a faithful group inside Israel, not of Christians: "here it is not the Christian, not a believer of this present age, who is in view; it is the faithful few left in Israel" (The Bible Treasury). Others apply it to believers today.
The two pictures are not repeats of each other. Kelly sets them against the religious teachers of that day, the scribes and Pharisees:
For the disciples, this position goes beyond "the salt of the earth." That stood for righteousness — not the outward kind shown by the scribes and Pharisees, but lowly and real in God's sight. "The light of the world," on the other hand, is grace shining out, and it cannot be separated from confessing Christ. Salt preserves, but it does not make everything visible the way light does.
Where the salt fails, nothing else can supply what is missing:
But He adds words — most serious words — "if salt has lost its taste, how shall its saltiness be restored?"... By this question He showed that the true and holy taste, once lost, could never be repaired. Grace may still work in people here and there, but the pure position cannot be brought back. Salt is simply salt. Nothing outside can give the saltiness that disappears.
The verse does not settle every question people bring to it. Kelly warns against forcing an outside debate into these words:
He is not now speaking of the question whether a saint can fall away or not. People go to Scripture with their own questions, and twist the word of God to fit their earlier thoughts... He is speaking of people who hold a certain position. Some may hold it carelessly, or even falsely. Then everything they once had fades away.
Salt without taste ends in public contempt. That warning reaches beyond one person:
Salt is a picture of the influence going out from the testimony to the holiness of God. Anyone whose testimony does not have this power is useless. For this reason the nations will trample Jerusalem, the city that rejected its own King (Luke 21:24). Christendom has had the good news of grace and salvation in Christ for centuries. It too will fall away from God and come under His judgment.
- Salt preserves. It is sharp, not sweet — it guards from decay and holds fast what is right.
- Covenant salt. God required salt in every offering, marking His keeping, sanctifying power that should now show in His people.
- Earth, not world. Salt works where God's testimony is already known; light shines out where it is not.
- Taste lost. Nothing outside salt can give back the one quality that makes it salt.
- Trampled. Where the taste is gone, people throw out the empty claim of faith and trample it — the fate warned of for Jerusalem and Christendom alike.
*Ye* are the light of the world a city situated on the top of a mountain cannot be hid.
The Lord has just called His followers salt; now He tells them what they are to the wider world. The picture He uses is a hilltop city — no one can miss it. The commentators press two questions. Where does this light come from? And what happens when those who carry it try to stay out of sight?
The two images point in different directions. One writer separates them, and notes that the disciples never chose to be this light:
The salt of the earth is a different thing from the light of the world. The earth, I think, means the sphere that already claimed to have received light from God. That light put it in relationship with Him, and gave it a definite shape before Him. The disciples of Christ were the preservative principle in the earth. They were the light of the world, and the world had no light of its own. This was their position, whether they liked it or not. It was God's purpose that they should be the light of the world. No one lights a candle to hide it.
The change of figure marks a change of direction. Salt keeps something from going bad; light travels:
But now, in verse 14, we have not only the principle of righteousness, but of grace — grace flowing out in strength. Here He gives the disciples a new title for their public testimony — "the light of the world." Light spreads. The salt is what ought to be inward, but the light is what scatters itself abroad. "A city set on a hill cannot be hidden." Its testimony was to spread all around.
Jesus also called Himself the light of the world. So the same title on His disciples must mean something different. One writer explains the difference with the moon:
Our Lord says, "As long as I am in the world, I am the light of the world" (John 9:5). But in view of His absence His saints are called by Him the "light of the world" (Matt. 5:14; Phil. 2:15). Saints are light in the Lord (Eph. 5:8). They are here to show the moral characteristics of Christ to people who are in darkness. And the whole source and power of their light rests in the Lord of heaven. The world cannot see Him, but He shows Himself to His own by faith and in the Spirit. The moon shines at night because it stands in the light of the sun. In the same way, saints shine while Christ is away, because they stand in the light of the risen Son of God.
Anyone living in Israel would have seen the picture at once:
"A city set on a hill cannot be hidden." An enemy planning an attack could see it. So could a traveller looking for a place to stay. By day its white walls and buildings shone bright. By night the lights of the houses gave it away. So the walk of the Lord's disciples ought to be a light in this world, seen by everyone.
Some have argued that the true company of believers is invisible. One writer answers that:
But I read in Scripture, "You are the light of the world." What use is an invisible light? "A city set on a hill cannot be hidden." To call the true church invisible settles the question at once. It admits that the church has lost its original and essential standing. It admits that the church has left God's purpose and the order He gave it. God did not light a candle to put it under a basket. He lit it to set it on a lampstand and give light to everyone in the house. If it has become invisible, it no longer serves the purpose God formed it for.
Commentators differ over whom the Lord is addressing here. Some hold that these words describe a faithful Jewish remnant who will bear witness after the church is taken away, saying that "as Matthew 5:13-14 shows, these godly Jews will be the salt of 'the earth' and the 'light of the world'" (H J Vine). Others press the passage directly on believers today:
Fellow believer, I urge you not to skim over or dodge the position the Lord gives you here on earth. These are His words: … "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." Let us live this out, instead of letting it slip past or pushing it off onto a Jewish remnant.
The lamp under the basket warns that something of our own can cover the light:
No one should put a lamp under a basket — that is, hide it behind what stands for man's own work. Let us not allow our work to get in the way of the light of Christ, who is the only source of light for people in darkness. The lamp set in its proper place will give light to all who are near it.
- Given, not earned — being the light is a position the Lord assigns, held "whether they liked it or not," not a status anyone works up to.
- Borrowed, not owned — the light is Christ's; His people shine as the moon shines, only because they stand in the light of the risen Son of God.
- Outward, not inward — unlike salt, which preserves quietly, light "scatters itself abroad" to a world that has none of its own.
- Visible, not hidden — enemy and traveller alike see a hilltop city. A light no one can see has stopped doing the job it was lit for.
- Clear, not covered — our own work in front of the lamp is what dims it. Keep the stand clear so people see Christ.