You are the salt of the earth: but if the salt has lost his savor, with what shall it be salted? It is good for nothing, except to be cast out and to be trodden under foot of men.
Also found in Luke 14:34-35
You are the light of the world. A city that is set on a hill cannot be hid.
Men do not light a candle and put it under a bushel, (or put it under the bed – Luke 8:16) (or put it in a secret place – Luke 11:33) but they put the light on a candlestick; and it gives light to all that are in the house. (Luke 8:16 says, that they who enter in may see the light.)
Nothing is secret, that shall not be made manifest; neither is any thing hid, that shall not be known and come abroad.
Let your light so shine before men, that they may see your good works and glorify your Father which is in heaven.