In the Sermon on the Mount, Jesus preached, “You are the salt of the earth” (Matt. 5:13). Why did Jesus use a salt metaphor to describe His people?
In the ancient world, people valued salt in many ways. Before refrigeration and the canning of food, salt was the main way people preserved meat and fish. In addition, the taste of food mattered then (just as it still does today!). In both the first century and the twenty-first century, people used salt to season their food, and it is one of the oldest and most universal of food seasoning (see Job 6:6).
Given its beneficial properties, salt was an important trade commodity in the ancient world. People sometimes used salt as currency or money. On occasion, a Roman soldier’s pay was a negotiated amount of salt. This payment was called salarium, from which we get our word salary. The expression “not worth his salt” comes from this practice.
With this understanding of salt’s value and beneficial properties, the Lord Jesus, the master teacher, used salt imagery to help us understand how we are to function as Christians in a fallen world. Jesus says, “You are the salt of the earth”—we are to be people whose grace-filled lives act to preserve, flavor, and value those around us. I suspect that the first hearers of these words were stunned with the magnitude of the practical implications of the metaphor.