In Matthew 5:13 it reads "Ye are the salt of the earth: but if the salt have lost his savour, wherewith shall it be salted? it is thenceforth good for nothing, but to be cast out, and to be trodden under foot of men." Salt was a very valuable mineral in those days and was regarded as a precious commodity. D&C 103:9-10 says that "For they were set to be a light unto the world, and to be the saviors of men; And inasmuch as they are not the saviors of men, they are as salt that has lost its savor, and is thenceforth good for nothing but to be cast out and trodden under foot of men."
We need to be the saviors of men and not lose our savor. This means that we need to "have peace one with another"(Mark 9:50) and be who we say we are(salt without savor is like not telling the truth). If we do these two things then we will have savor. In a conference a while back we were asked what some of the qualities of salt are. We said things like, it adds taste, it preserves, and it is an essential mineral We were also told that salt will conduct electricity if poured in water.
This led into the next couple of verses perfectly. Matthew 5:14-16 says "Ye are the light of the world. A city that is set on an hill cannot be hid. Neither do men light a candle, and put it under a bushel, but on a candlestick; and it giveth light unto all that are in the house. Let your light so shine before men, that they may see your good works, and glorify your Father which is in heaven." The best way to share our testimony is to be an example of what we believe.
As long as we have our savor, we will become the saviors of men if we let our example shine forth.