You are the light of the world. A city set on a hill cannot be hidden; In the same way, let your light shine before men, so that they may see your good works and give glory to your Father in the heavens. (Matthew 5:14, 16)
Being the light of the world is pre-eminently applied to Jesus in the Scriptures (Matt. 4:16; Luke 2:32; John 1:4; John 8:12; Isa. 49:6), because he is, in the moral world, what the sun is in the natural world. The apostles, Christian ministers, and all Christians are lights of the world, because they, by their instructions and example, show what God requires, what is the condition of man, what is the way of duty, peace, and happiness the way that leads to heaven. As the city on the hill, Christians must be seen; they ought to be holy, harmless, and undefiled.