Having thus carried the figure as far as it will serve him, the Master changes it for another, which he can carry farther. For salt only preserves from growing bad; it does not cause anything to grow better. His disciples are the salt of the world, but they are more. Therefore, having warned the human salt to look to itself that it be indeed salt, he proceeds: 'Ye are the light of the world, a city, a candle,' and so resumes his former path of persuasion and enforcement: 'It is so, therefore make it so.'--'Ye are the salt of the earth; therefore be salt.'--'Ye are the light of the world; therefore shine.'--'Ye are a city; be seen upon your hill.'--'Ye are the Lord's candles; let no bushels cover you. Let your light shine.' Every disciple of the Lord must be a preacher of righteousness. Cities are the best lighted portions of the world; and perhaps the Lord meant, 'You are a live city, therefore light up your city.' Some connection of the city with light seems probably in his thought, seeing the allusion to the city on the hill comes in the midst of what he says about light in relation to his disciples as the light of the world. Anyhow the city is the best circle in which, and the best centre from which to diffuse moral light. A man brooding in the desert may find the very light of light, but he must go to the city to let it shine. From the general idea of light, however, associated with the city as visible to all the country around, the Lord turns at once, in this probably fragmentary representation of his words, to the homelier, the more individual and personally applicable figure of the lamp: 'Neither do men light a lamp, and put it under a bushel, but on a lampstand, and it giveth light to all that are in the house,' Here let us meditate a moment. For what is a lamp or a man lighted? For them that need light, therefore for all. A candle is not lighted for itself; neither is a man. The light that serves self only, is no true light; its one virtue is that it will soon go out. The bushel needs to be lighted, but not by being put over the lamp. The man's own soul needs to be lighted, but light for itself only, light covered by the bushel, is darkness whether to soul or bushel. Light unshared is darkness. To be light indeed, it must shine out. It is of the very essence of light, that it is for others. The thing is true of the spiritual as of the physical light--of the truth as of its type.