You are the salt of the earth; but if salt has lost its taste, how shall its saltiness be restored? It is no longer good for anything except to be thrown out and trodden under foot. Matt. 5:13, RSV.
With verse 13 Jesus shifts from His exposition of Christian character to a short section on a Christian's influence. But the two are closely related. After all, a Christian's influence depends upon character. Without a "Christian" character, there can be no "Christian" influence. The salt must be salty to be effective.
Salt has many functions. Societies without refrigeration use it as a preservative. But in order to be effective, salt must penetrate the food. Salt left a fraction of an inch away from food can neither preserve nor flavor.
Jesus describes Christians as "the salt of the earth." He has not commanded us to become salt, but has stated a fact--"You are the salt." Christians function as salt by intermingling with the surrounding culture. Only then can they carry out their God-given role of preserving and flavoring their society. Although Christians often do not realize it, their daily lives moderate the people and society around them as they live out the Beatitudes. They "flavor" the world through the little kindness they show, the humility they demonstrate, and so on. Even proud and hardened people often find it difficult not to respect true Christians, although they may not choose to emulate them. Thus one effect of Christian influence is to slow down the personal and social degeneracy Paul so aptly describes in Romans 1:18-32.
Salt is salt! Salt is salty! Without saltiness it is not salt!
How, therefore, can salt lose its saltiness? It can't. If it's not salty, it's not salt.
"So what?" you may be asking at this point. "What does this mean for my life?"
It means everything. Since Christians cannot choose not to be salt, the only thing that they can do is to elect not to function as salt, to reject the God-given role of salt.
And how can I do that? By not being like Jesus, who lived and died for the good of others. By failing to mix with the world and contributing a preserving influence.
With such choices individuals lose their saltiness. They are no longer salt (i.e., Christians). Such have become a part of the problem rather than the solution.
The moral of the story is simple. It makes a difference what principles we accept in our lives and how we relate to people in daily life.