Jesus described His followers as the salt of the earth in Matthew 5 as part of His Sermon on the Mount: “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 underfoot” (verse 13).
There were two purposes for salt in the first century—preserving food and enhancing flavor. Both of those purposes may apply here, or Jesus may have been speaking in a more general sense.
By using this salt metaphor, Jesus may have meant that His disciples are called to be “preservatives” in the world, slowing down the advancement of moral and spiritual decay. Psalm 14:3 says, “All have turned away, all have become corrupt; there is no one who does good, not even one.” Believers are to preserve truth and goodness in a fallen world.
Salt was also used as a flavor enhancer. Jesus may have been instructing His disciples to “enhance” the flavor of life in this world—enriching its goodness and making God’s work stand out from the normal way of doing things. “But love your enemies, do good to them, and lend to them without expecting to get anything back. Then your reward will be great, and you will be children of the Most High, because he is kind to the ungrateful and wicked” (Luke 6:35). As believers behave in ways that reflect God’s nature, they accentuate the difference that Jesus makes in one’s life.
Since Jesus’ exact meaning is not specified, perhaps He was not pointing to one specific application, but to salt in a general sense of value and usefulness. In those days, salt was a valuable commodity (the word salary comes from an ancient word meaning “salt-money”). Perhaps Jesus was telling His disciples how important their ministry would be.
Of course, the value of salt lies in its effect on its surroundings. Salt makes an impact. After telling His disciples that they are the salt of the earth, Jesus goes on to say, “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 underfoot.” Can salt become less salty? Strictly speaking, no. Sodium chloride is a stable compound and can’t become less of itself. What was Jesus saying then? There are several possibilities:
1) Jesus may have been referring to the “salt” that was collected from the Dead Sea by evaporation. The substance resembled pure salt, but it wasn’t effective for preservation or for seasoning.
2) Jesus could have been referring to the rock formations in which people would store their meat. Once the salt leached out of the rocks, the rocks were no longer effective to preserve the meat.
3) Others have speculated that Jesus was referring to the salt blocks that bakers used in their ovens. Eventually the heat would make these salt blocks useless.
4) Yet others think Jesus was referring to a saying of the time: “Can salt lose its saltiness?” It’s a rhetorical question because salt can’t become less salty. True disciples of Jesus cannot lose their saltiness. They are new creations and completely changed. Someone who is an imposter cannot become salty again. The imposters are to be “thrown out and trampled underfoot” because they have no effectiveness.
How does Jesus’ statement about the salt of the earth apply to us today?
Matthew 5:13 tells us that we are valuable in our role as disciples of Christ. God uses us to impact the people around us. Whether we are slowing down the moral decay or enhancing the spiritual “flavor” of the world, God has created us to be a positive impact. As followers of Christ, we are called to be different and to live righteous lives.