The Savior called people before He started to teach them. In both this statement and in the “light of the world” statement, the 3 Nephi version adds the phrase “I give unto you to be,” replacing the Matthew 5 present indicative words “ye are.” “I give unto you” is equivalent to “this is your calling” or “This is your assignment.” In other words, “I give unto you this responsibility to be this kind of people.” Then He proceeded to enable them by instructing them on how they will have the abilities, the powers, and the gifts to accomplish what He is asking them to do.
“I give unto you to be the salt of the earth,” is a charge, given with a warning. This charge redefined who the participant is to become because of this covenant. Interestingly, every sacrificial covenant in ancient Israel had to have salt added as a part of it. In the covenant that God has with the world, we will become the covenant figures of the world to provide the necessary salt to make the covenant efficacious.
The Book of Mormon says the salt “loses its savor.” The early Book of Mormon manuscripts support the reading, “its savor.” We usually do not think of salt being masculine and, in fact, the Greek word for salt is neuter. In Matthew chapter 5, the King James version says that it has lost his savor. For some reason the King James translators unnecessarily thought that salt should be masculine. The Book of Mormon text is gender neutral.
In the Greek text, there is no noun equivalent to “savor.” The phrase is ean de to halas m?ranth?. Deterioration is implicit in the meaning of the verb mrain?, here in the form m?ranth?. That verb is derived from the adjective m?ros (dull, stupid, the origin of “moron”), and meant “to become foolish,” but with salt and other flavorings, it was used to mean “to become insipid,” or “flavorless.” The adjective (m?ros) is used in the parable of the wise man and the foolish man, who is there called moron. Maybe it really should be translated, “if the salt become foolish.” We will learn at the end of the Sermon on the Mount how we can become foolish. Remaining pure and apart is important here. He has appointed us to be apart and pure, and not to be foolish or contaminated by the impurities of the world around us.