In Matthew’s record of the sermon on the mount Jesus speaks of His disciples as the “salt of the earth.” Salt is flavoring, and is used in preserving meat. We Christians are God’s means of saving the world from eternal punishment. We are to season this bland and sinful world! We are to preserve it from the putrefying nature of sin! If we, the salt, lose our flavor, then we are not doing our job, and are “good for nothing.”
We are “the light of the world.” Of course the only source of spiritual light is God (1 John 1:5). If we are Christ’s, and we are living the life a Christian is called to live, being the salt of the earth, then our light is going to shine. If our light is shining, then it is like “a city that is set on a hill” that cannot be hidden! We must lead a life pleasing to God, and our light will shine!