There are about 14,000 uses for salt according to the salt institute. It is: a cleaning agent, a seasoning agent, a preservative, it increases the temperature at which water boils and decreases the temperature at which water freezes, it removes odors. It also: deters ants, quells grease fires, repairs walls, kills poison ivy, provides traction on icy surfaces, and cleans all sorts of wounds, to name a few uses.
I believe Jesus chose his words carefully when He called his followers salt. His intent was to show them that they had many uses to God, and they were to remain pure so that they may be useful.
Everyone sins, but there is a choice to be had after the sin is committed. The sinner must either choose to continue the sin, or repent (turn away) from the sin.
Many sinners choose to live in the sin, even those who are in Christ. This causes friction or distance between them and God, thus losing any effectiveness the sinner could have for Christ.
A sinner must expose their sin, at least to one other trusted individual to create an accountability partner. Then they can call on them when thoughts or feelings arise to continue their sin. The accountability partner must remain silent regarding this sin unless their silence would cause harm to the sinner or those related to the sinner. This creates a trust bond and allows the sinner to be truthful and honest regarding their sin.
Once the sinner is free from their sin, then they have regained their saltiness. Their struggle may then be shared to further display how God has worked in their life. This allows their light to shine and their city to be placed on a hill. A highly defensible position, but a highly visible target. With Christ, however, no one can stand against them.
“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.
You are the light of the world. A town built on a hill cannot be hidden. 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. In the same way, let your light shine before others, that they may see your good deeds and glorify your Father in heaven.” – Matthew 5:13-16