Not only are we salt, according to Jesus (see our last blog), we are light. Again (as it was when Jesus talked about salt) the construction in the Greek is emphatic: “You, you alone and no others are the light of the world!” This should be no surprise, because Jesus said of Himself: “I am the light of the world” (John 8:12), and here He teaches us that we are meant to reflect this light in our own lives. Paul wrote that we are to “become … children of God without fault in a crooked and depraved generation, in which you shine like stars in the universe…” (Phil. 2:15), and that God has “shone in our hearts to give the light of the knowledge of the glory of God in the face of Christ.” (2 Cor. 4:6). The next thing Jesus says is this: “A city set on a hill cannot be hidden.” This statement seems to give a practical application or consequence to His declaration that we are the light of the world. What does Jesus mean by describing the church as a “city on a hill”?
Clearly, it has something to do with visibility, and again a knowledge of the historical context comes in handy. In the Israel of Jesus’ day, houses were often built of white limestone. As such, they would gleam in the sun and could scarcely be hidden, particularly if set on a hill. At night, the light of hundreds or thousands of oil lamps would cast a glow over the hillside. Even as you would not build a city on a hill and try to hide it, neither would you light a lamp and set it under a bowl, verse 15 continues. A lamp is put on a lampstand to give light to everyone, and the church is set on a hill for the same purpose. Jesus was almost certainly thinking about the Old Testament prophecies concerning Jerusalem as a city of light lifted up before the nations who would come to it: “In the last days the mountain of the Lord’s temple will be established as chief among the mountains; it will be raised above the hills, and all nations will stream to it” (Is. 2:2). “Arise, shine, for your light has come, and the glory of the Lord rises upon you. See, darkness covers the earth and thick darkness the peoples, but the Lord rises upon you and His glory appears over you. Nations will come to your light, and kings to the brightness of your dawn” (Is. 60:1-3).
Jesus is reminding us that the church has taken the place of Jerusalem as the city of God in the same way that believers of Christ from every nation, Jew and Gentile alike, have taken the place of Israel as His covenant people. In the same way as a city on a hill gives out its light, day and night, God’s city will shine eternally: “The sun will no more be your light by day, nor will the brightness of the moon shine upon you, for the Lord will be your everlasting light, and your God will be your glory” (Is. 60:19). Jesus now commands us in verse 16 to let our light shine before the world, that everyone may see our good deeds and glorify God. The church is the most powerful solar energy device ever made. We are designed and created to take the light of the universe and reflect it into the world around us, imparting the energy by which that universe was created and by which Jesus Christ was raised from the dead. Without us, the people and nations around us will descend into darkness. This incredible power and responsibility is ours.