Lord, they have been the salt, they have been the light of the world!

No sooner has he used the symbol of the salt, than the Lord proceeds to
supplement its incompleteness. They were salt which must remember that
it is salt; which must live salt, and choose salt, and be salt. For the
whole worth of salt lies in its being salt; and all the saltness of the
moral salt lies in the will to be salt. To lose its saltness, then, is
to cease to exist, save as a vile thing whose very being is
unjustifiable. What is to be done with saltless salt!--with such as
would teach religion, and know not God!

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