"You are the salt of the earth; but if salt has lost its taste, how can its saltiness be restored?  It is no longer good for anything, but is thrown out and trampled under foot."

Salt has a powerful flavor.  It is used to condition and improve the taste of many foods.  But it is never used by itself.  Even so, each day we are placed into situations and events for the good purpose of the Father to be salt.  This is as it is written, "As they go through the Bitter Valley they make it a place of springs." (Psalm 84.6)  But what if we go flat?  Salt has a powerful, distinct flavor but if it goes flat it disappears into the taste of the food.  So too does our saltiness disappear when we fall for the world or fall into the gang around us and no longer give God glory though the witness of a Christian life.  What then are we good for when that was our purpose?  Do not imagine that you will be judged equally with those to whom you were sent.  They had little flavor: you were sent to flavor them with the potent witness of your Christian life.  But you wanted to become one of them and had no interest in standing out.  Therefore you yourself can't be restored (except through penance).  Can salt itself be salted?  No it must be thrown out.  The food it was put on can still be flavored with good salt, but you, if you have lost your taste for the faith, are no longer good for anything and must be moved aside and replaced by others.

Hold fast to the word of life and you will remain salty, otherwise the desire for other things will make you go flat. (Mark 4.19)  "Do all things without murmuring and arguing, so that you may be blameless and innocent, children of God without blemish in the midst of a crooked and perverse generation, in which you shine like stars in the world." (Philippians 2.14-15)