You are the salt of the earth;
but if the salt loses its flavor, how
shall it be seasoned?  It is then good
for nothing but to be thrown out
and trampled underfoot by men.

You are the light of the world.
A city that is set on a hill cannot be hidden.

Nor do they light a lamp and put it under a basket, but on a
lampstand, and it gives light to all
who are in the house. 

Let your light so shine before
men, that they may see your good
works and glorify your Father in heaven.
Matthew 5:13-16