You are the salt of the world; but if the salt has lost its taste (purpose), how can it be made salty? It is no longer good for anything, but to be thrown out and walked on by people (when the walkways are wet and slippery).
Matthew 5:13 (AMP)
Let your speech at all times be gracious and pleasant, seasoned with salt, so that you will know how to answer each one (who questions you).
Colossians 4:6 (AMP)