Commentary: Salt has long been recognized for its preservative role. Long before there were refrigerators our ancestors salted meats and fish in order to preserve them for later use. It was the most common preservative and flavoring agent in the ancient world.

You probably seldom consider it, but salt is also essential for your survival. Salt affects electrical conductivity through the body - it governs how our hearts beat, how signals are transmitted along our nerves and in our brains, and controls many other vital processes in your own body. Even the most primitive of peoples have realized that salt is necessary for life. Countless wars and campaigns have actually been fought for control of salt sources.

Salt preserves, it is necessary for life, and of course it adds taste to food. Regarding that quality, Job asked the question: Job 6:6 "Can flavorless food be eaten without salt? Or is there any taste in the white of an egg?" He calls this unsavory food, "loathsome."

So everyone hearing this parable would immediately have understood why Jesus said "Salt is Good." They also would have agreed about how worthless salt would be if it lost its good qualities. Now how could that happen? How could salt loose its saltiness?

Well the salt in Palestine was taken from natural sources and it was highly adulterated with other minerals, it was possible for water, for instance, to leach out the sodium and leave you with a substance that might look like salt, but neither tasted nor acted like salt. Such a substance unlike the waste from the kitchen wouldn't even be valuable on the compost heap or the dung hill, it couldn't be used as a fertilizer most other waste products, so it had less value than dung. What would you do with that? Throw it out!

Jesus though is not teaching a lesson here about household economics or chemistry. He is drawing an analogy, teaching a mini-parable, connected to what he had been teaching about true and false followers. Jesus said to his disciples "You are the salt of the earth." What made them salty? How did they salt the earth? What made them salty was the Gospel. The good news of Jesus Christ.

The Gospel, like salt, comes into a world filled with death and decay, and it exercises a preserving function. It is a critically necessary element for all true spiritual life. Where it is truly present it adds a distinctive flavor. The very words of a Christian should be as Paul puts it, "with grace, seasoned with Salt." A true Christian life and walk exudes the gospel. It is opposed to the death and putrefaction of worldliness, and its aim is to arrest and reverse the rot. It is opposed to: A) corrupt doctrine and B) corrupt morals, and it is this gospel salt that should make such a difference in the world. The Puritan minister Matthew Poole puts it this way:

"You are the salt of the earth, through the grace of God bestowed upon you. If it were not for the number of sound and painful ministers, and holy and gracious persons, the earth would be but a stinking dunghill of drunkards, unclean persons, thieves, murderers, unrighteous persons, that would be a stench in the nostrils of a pure and holy God."