13“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 trampled under people’s feet.
This probably refers to the origin of salt and not to the use of the salt. Salt was a very important and precious commodity that could be used for seasoning food (Job 6:6) and as a preservative.
13 “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 trampled under people’s feet.