Opening the Word: Salt of the earth

It is small, simple and composed mostly of something that doesn’t sound tasty at all: sodium chloride. But the importance of salt in the ancient world is hard to overstate, even if it is usually taken for granted in our own day. Salt was valued so much among the Romans that spilling it was interpreted as a bad sign. The word “salary” is derived from the word “salt,” in reference to payments made to Roman soldiers; a bad soldier was sometimes described as “not worth his salt.” 

Similarly, we are all familiar with the expression, “He is the salt of the earth.” That phrase comes from today’s Gospel and Jesus’ declaration in the Sermon on the Mount, “You are the salt of the earth.” This was high praise when we consider that salt often played a role in the rise and fall of civilizations. Before refrigeration and other modern means of preserving food, salt was vital to keeping food pure and edible, which in turn had a significant effect on the health, stability and success of ancient peoples. 

This important place and positive effect of salt is seen in passages in the Old Testament. In the Book of Job, the question is asked, “Can a thing insipid be eaten without salt?” (Job 6:6), and the author of Sirach states, “Chief of all needs for human life are water and fire, iron and salt ... ” (Sir 39:26). Newborn babies were rubbed with salt (see Ez 16:4), and certain burnt offerings were sprinkled with salt (Lv 2:13; Nm 18:19; Ez 43:24), which symbolized the indissoluble relationship between God and the chosen people of Israel. 

In the positive sense used by Jesus, to be salt of the earth is to work to preserve life, to be pure and to exemplify holiness. “Jesus signifies that all human nature has ‘lost its taste’,” wrote St. John Chrysostom, “having become rotten through sin.” This plays on the double meaning of the Greek language, in which the phrase “loses its taste” can also mean “has become foolish and dull.” Mankind has lost its moral awareness and sense of holiness, and Christ’s disciples are to restore what has been lost, drawing men and women to the source of eternal life. 

Jesus then said, “You are the light of the world.” This builds upon St. Matthew’s reference, in the previous chapter, to “the people who sit in darkness” having “seen a great light” (Mt 4:16; see Is 9:1-2). The reference to “a city set on a mountain” is also drawn from the prophet Isaiah, who envisioned a time when “The mountain of the Lord’s house shall be established as the highest mountain” (Is 2:2). That is “the city of the living God, the heavenly Jerusalem” mentioned in the Epistle to the Hebrews.  

“The humble city is the society of holy men and good angels,” wrote St. Augustine in “City of God,” “the proud city is the society of wicked men and evil angels. The one city began with the love of God; the other had its beginnings in the love of self.” 

Those who are motivated by a vanity and narcissism live in darkness; they are consumed by themselves and destined for eternal darkness if they do not change their ways. 

But those who follow Christ are filled with the life and light of God: “Just so, your light must shine before others.” Why? So that the world — filled with sin, lacking salt and the taste of goodness — will see the good deeds done by grace and glorify God.  

“It is only for the sake of God’s glory that we should allow our good works to become known,” noted St. Augustine. That should be the goal of every disciple worth his salt. 

Carl E. Olson is the editor of