"Verily, verily, I say unto you, I give unto you to be the salt of the earth; but if the salt shall lose its savor wherewith shall the earth be salted? The salt shall be thenceforth good for nothing, but to be cast out and to be trodden under foot of men."
– 3 Nephi 12:13 (see also Matthew 5:13)
Salt is used to bring out the flavor in dishes, and also used as a preservative. It is a valuable mineral, and has been used in some ancient cultures as a form of money. So when Christ teaches us to be the salt of the earth, what does this mean?
As disciples of Jesus Christ, we have the good news of the gospel to share with the world. We can share a spiritual flavor with those around us, and season our speech, our actions, and our lives with spirituality. We become the salt of the earth as we study the word of God, keep the commandments Christ has given us, and strive to live a life of worthiness.
How does salt lose its savor? Have you ever really thought about this? You can keep a canister of salt on your shelf almost indefinitely, and the salt stays salty and potent indefinitely. You can mix salt in food, and it will increase the flavor and savoriness of the dish. It doesn't lose its savor. The only thing that makes salt lose its savor is mixing it with dirt.
So think about that for a minute. As God's spiritual salt, we can lose our spiritual savor when we allow filthiness into our lives. There are so many different kinds of filth that can damage our spirituality - what we say, what we do, who we associate with, things we pursue for entertainment, the list can go on and on. We have to be careful and show discretion about these things. If we do this, we will not lose our spiritual savor.
Personally, I don't want to be cast out and trodden under God's foot, worthless to Him. There is nothing I want more than to be valuable in my Lord's eyes and to be put to good use for Him. I am made for Him and His service, and I long to stay that way.