Let’s read that portion you are referring to in your good question.  Matthew 5:14-16 are the words of the Lord Jesus.  There, He says, “Ye are the light of the world. A city that is set on an hill cannot be hid. Neither do men light a candle, and put it under a bushel, but on a candlestick; and it giveth light unto all that are in the house. Let your light so shine before men, that they may see your good works, and glorify your Father which is in heaven.” 

It is important to see who the Lord is addressing in these words, so let’s go back and read Matthew 5:1-2, “And seeing the multitudes, he went up into a mountain: and when he was set, his disciples came unto him: And he opened his mouth, and taught them…”  We see the Lord left the multitude to be alone with His disciples so that He might teach them things concerning Himself and how we, as His disciples, should behave.  The Lord makes two great points here.  We (believers) are the light of the world, and we should let our light shine.  Let’s look at these two important points.

YE ARE THE LIGHT OF THE WORLD – In John 8:12, the Lord declares Himself as the light of the world.  In John 9:5, He qualifies that statement by saying, “As long as I am in the world, I am the light of the world.”  In this instance, the Lord was about to give sight to a man who was born blind.  So, He used that occasion to speak of Himself, as the One who not only IS the light, but also able to GIVE light to the darkened minds of men. So, we learn that our Lord’s miracles were designed, not only as proof of His mission, but to be examples of the power which he possessed as the TRUE LIGHT (John 1:9).  The Lord is still the light of the world, but He was speaking here of His direct ministry while on the earth.  Indeed, the Lord is the light of the world so that those who believe on Him, “should not abide in darkness.” (John 12:46).  Our blessed Lord is the very source of light, while believers are the reflection of His light.  Even as the moon reflects the light of the sun, we, as believers, reflect the light and glory of the Son.  We who know the Lord are His representatives in the world.  What a grand honor!  We are ambassadors for Him as we read in 2 Corinthians 5:20, “Now then we are ambassadors for Christ, as though God did beseech you by us…” 

LET YOUR LIGHT SHINE BEFORE MEN – Even as a city that sits upon a hill cannot be hid, as the light of the world, we are given the privilege and responsibility to shine the Lord’s light in front of all men…not so that we will be noticed and admired, but that through our good works, the Lord might be glorified.  The light was not given to us so that we might hide it.  A light is to be held high so that its existence might be great and effective in showing the love and glory of our Lord…so that others might come to know and glorify our Lord.  The life that we live for the Lord is the light that will give light to others.  There is no room for boasting or for pride in the life of a Christian.  Have you been of service to the Lord?  Have you been effective in your testimony for the Lord?  Have others benefited by your faithful service to the Lord?  Do not think highly of yourself!  For all that we might do for the Lord, Philippians 2:13 reminds us of the source and power for that service.  “For it is God which worketh in you both to will and to do of his good pleasure.”  Our shining light will bring glory to the Lord.  If we try to attract attention to ourselves, we are trying to rob the Lord of His glory by seeking glory for ourselves.  May that never be said of any of us who love the Lord!

My dear fellow believer.  You ARE the light of the world.  DO NOT hide that light by pride, laziness, or apathy.  With your life, hold that light high so that others might see it and benefit from it.  The world is in constant darkness and needs constant light.  The Lord has entrusted us with this wonderful duty.  Let us look to Him to use us to glorify His name in a world that desperately needs Him.  (CC)  (706.2)