How to preserve the light

Matthew 5:13-16 Salt and Light 13“You are the salt of the earth. But if the salt loses its saltiness, how can it be made salty again? It is no longer good for anything, except to be thrown out and trampled underfoot. 14“You are the light of the world. A town built on a hill cannot be hidden. 15Neither do people light a lamp and put it under a bowl. Instead they put it on its stand, and it gives light to everyone in the house. 16In the same way, let your light shine before others, that they may see your good deeds and glorify your Father in heaven.