Summary: sermon 8 in a study in the Sermon on the Mount
“You are the salt of the earth; but if the salt has become tasteless, how can it be made salty again? It is no longer good for anything, except to be thrown out and trampled under foot by men. 14 “You are the light of the world. A city set on a hill cannot be hidden; 15 nor does anyone light a lamp and put it under a basket, but on the lampstand, and it gives light to all who are in the house. 16 “Let your light shine before men in such a way that they may see your good works, and glorify your Father who is in heaven.”
As we’ve continually observed, Jesus is describing the Christian and the character of the Christian in this chapter so far. He continues to do so in these four verses but here He specifically addresses what the Christian’s relationship is to the world.
In John 17 (quickview)  Jesus made the statement that we, like He, are not of this world, meaning that although we are still in the world, having become new creatures in Him we are now of another place.
However since we are still in the world we are to be something to the world, in His name, and this is really the only real and significant way we are to relate to this world while we are here.
We are salt and light.
So let’s look at these two words for a few minutes, trying not to fall into the trap of over-analogizing, but just getting the broad picture that these two images portray for us and then gauging how well we as individuals and we as the American church might be filling the role in which these words place us.
SALT AND SALTINESS
The first observation I want to make about this portion is that what Jesus says about salt is in one verse, and the other three verses are dedicated to the analogy of light.
So His statement about salt as it pertains to our relationship to the world is very short. Furthermore, note that Jesus doesn’t say, “You are the salt of the earth. Now salt is used for preservation and for flavoring and...” so forth.
He simply says, “You are the salt of the earth”, and then goes directly to the negative side and talks, not about the uses and usefulness of salt, but the uselessness of salt that has lost the properties that once made it useful.
Now the commentators go into very descriptive detail about how until very recent times there was no refrigeration, so people would preserve meats by rubbing them with salt and how it would retard putrefaction. And they talk about the custom of showing courtesy to guests in giving them salt for their food and so on.
I just don’t think I need to explain to any of you the properties and uses of salt. It was the most common seasoning of ancient times and I’m sure it is today, which may answer any question as to why Jesus did not feel it necessary to go on and explain what He meant by likening His followers to salt as they apply themselves to the world around them.
So having said that, we go back to verse 13 and see that He follows these seven short words, ‘You are the salt of the earth”, with this very blunt and straight-to-the-point declaration.
If salt has lost its saltiness there’s no point in even calling it salt anymore! Like the joke about what to call a fly if it has no wings. Do you call it a walk? Un-salty salt is just white grains of garbage. Throw it on the ground and let it mix with the dirt because that is what it has become.