The same way, if you say you are a believer, but never show fruit of what you say you believe.
If you say you are a believer to others, then you are the salt of the earth. Now what you do to act on what you believe will show how flavorful or salty you are.
If you salt your food, because you want the flavor of salt, then you find that the salt your using has no flavor, you will throw it out because what good is it.
If someone tells you they believe but does nothing to show it. They are like salt that has lost its flavor.
Are people listening to what you say you believe in, and are you showing them you are the salt of the earth? Or are they about to throw you out because you say you believe in something, and it is only lip service?