"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
So far we’ve given most of our attention to the “salt” aspect of Jesus’ words. Let give some thought to the “light” aspect. After declaring that disciples of Christ “are the light of the world,” Jesus points out that a city set on a hill cannot be hidden. The city’s elevation mattered, especially in those days when warfare was largely based on walled cities defending themselves from invaders. The walls mattered, and if the walled city was elevated, it was all the more defensible. From atop the walled city on a hill, the people in the city could clearly see their attackers, and those outside could see how strong the city was.
Having given that illustration, Jesus employed a similar illustration of a lamp. A lamp on the floor does not illuminate the room as fully as a lamp on an elevated lampstand. Worse still, a lamp covered by a basket gives no light at all and is therefore virtually worthless.
Jesus then connected the two illustrations with His point. As “the light of the world,” God’s people are to shine in such a way that we cast the light of Christ and the gospel in the broadest manner possible. We dare not hide our light or we make ourselves worthless. We must position ourselves where the light will shine the brightest. As important as our homes and churches are, if we shine only in these hiding places, we are not acting like “the light of the world.” Disciples must get out into the spiritually dark world for our light to be seen and for people to be drawn to Christ.
Verse 16 is not about performing righteous acts for our own glory. It is about illuminating the sin-darkened world with the light of Christ and the gospel so that people will “glorify our Father in Heaven.”
One final thought on this: We are not the source of light, nor do we have any light in and of ourselves. We are more satellites than lights, in that sense. Jesus is “the Light of the World” (John 8:12). Our responsibility is to be “in Him,” and “abide in Him” so we most accurately and fully reflect His light to our world. It is Jesus the world needs, we are but His agents!