Salt of the Earth–Light of the World

You are the salt of the earth, but if the salt becomes flavorless, how can it be made salty again? It is no longer good for anything except to be thrown out and trampled under people’s feet.

You are the light of the world. A city set on a hill cannot be hidden. Nor do people light a lamp and put it under a basket–they put it on the lamp stand so that it gives light to everyone in the house. In the same way, let your light shine before others so that they can see your good works and give glory to your Father in heaven.
Matthew 5:13-16

Jesus begins the Sermon on the Mount with a dynamic list that describes his life and the life of his apprentices, and it doesn’t take long for the reader/listener to realize that Jesus is describing a life of activity and engagement. He mentions characteristics like showing mercy and being a peacemaker that are a call to participate in life in positive ways– showing compassion to the hurting, opposing injustice, confronting prejudice, standing for righteousness, seeking reconciliation between people in conflict with God or one another–this is how Jesus lived and how he wants his followers to live, but he says there will be a cost: persecution. Jesus then uses two familiar images to illustrate the impact his apprentices will have on the world around them: they will be salt and light.

Why does Jesus use these two metaphors to describe his followers? Perhaps the most basic reason is that both substances are essential for life on earth. The human body needs salt to live, and all life on earth requires light.

• Salt had many uses in the ancient world, but it was especially treasured as a food preservative. Salt slows the corruption in perishable items like fish and meat. Properly salted provisions would keep for months and could be the difference between survival and starvation. When Jesus likens his apprentices to salt, he is saying their presence will slow down corruption in their family, neighborhood, and world. Salt was also valued for its seasoning properties, and Jesus may also have had this in mind when he used the metaphor. Salt adds zest and flavor and makes food more interesting and enjoyable.
• When Jesus likens his disciples to “light,” they were probably reminded of Isaiah’s prophecy about Israel: “For behold, darkness shall cover the earth, and thick darkness the peoples, but the Lord will shine upon you, and his glory will be seen upon you. All nations will come to your light, and mighty kings will come to see your radiance” (60:2-3).

Salt and light have something else in common besides being essential for life on earth: both are catalysts. Light and salt radically change the environment they enter.

• When salt is put on fish or meat, it does not simply change the taste; it alters the chemical properties of the food and immediately begins to slow down decomposition.
• The same is true of light. It doesn’t just add something to help us see better in the darkness; light eliminates darkness and creates an entirely new environment.

These two metaphors describe the essential nature of God’s people, but they also speak to the woeful condition of the world we live in. The world needs light and salt because it is filled with darkness and corruption. But what does spiritual salt and light look like in today’s world?

Next: How to be salt and light.