“You are the salt of the earth, but if salt has lost its taste, how shall its saltiness be restored? 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, but on a stand, and it gives light to all in the house. In the same way, let your light shine before others, so that they may see your good works and give glory to your Father who is in heaven.” Matthew 5:13-16

Every Lord’s Day I conclude our worship service by reminding us before the benediction that our Triune God sends us out into the world as salt and light. These metaphors are taken from Jesus’ words to his disciples in the Sermon on the Mount. But what do they mean? This month we will consider how Christians are the salt of the earth and next month we will consider how we are the light of the world.

In our day, we primarily use salt to enhance the flavor of our food, but in the days before refrigeration and chemical preservatives, salt was primarily used to keep meat from decaying while it was stored. If we apply this historical understanding to Jesus’ words, we learn that Jesus was teaching that Christians are a blessing to the world because we preserve society from becoming rotten. Herman Ridderbos, in his commentary on Matthew’s gospel, explains:

Jesus first calls his disciples the ‘salt of the earth.’ What he had in mind here is the preservative power of salt. By ‘earth’ he meant human society and, beyond this, the whole world as the setting for life. Jesus’ disciples thus have a preservative influence on human society, and through it on all other things. They counteract the corruption and decay that is at work in the world. They are not a source of renewal in the sense of re-creation, for it is the society of this present world that they seek to influence. Within it they try to call people back to God’s promise and blessings. In so doing they offer a rich blessing, even to the world in its present state.

I believe it’s significant that Jesus used such expansive terms as “world” and “earth” as he spoke to a group of disciples who had probably not traveled outside of the regions surrounding Jerusalem. Traveling long distances was much more difficult in those days. Yet Jesus, knowing that after his resurrection his disciples would be scattered and sent out into Judea, Samaria, and to the ends of the earth, was preparing them for their role in the whole known world as his followers from every tribe, tongue, and nation. They would need to maintain their distinctiveness as his followers, even under the pressures of rejection and persecution. This is why Jesus warns of salt losing its saltiness. Dan Doriani, in his commentary on Matthew, explains: “To grasp Jesus’ point, we need to understand that in ancient times ‘salt’ was a piece of rock dug from the ground and containing many impurities. Water could wash through it, dissolving the sodium chloride (the salt mineral), and leaving a residue that looked like salt rock and even retained its original shape, yet lacked the flavor of salt.” This residue would then be used to pave roads since it was not suitable for food use.

And so we need to ask ourselves: “Am I salty? Or have I become indistinguishable from unbelievers in the way I speak, think, and live?” Jesus exhorts us to be salty so that the people we are around may see our good works and give glory to our Father who is in heaven. The Apostle Peter echoes this thought when he writes, “Keep your conduct among the Gentiles honorable, so that when they speak against you as evildoers, they may see your good deeds and glorify God on the day of visitation” (1 Peter 2:12). Our righteous deeds, coupled with our verbal witness to Christ’s atoning work, are among the powerful means God uses to draw unbelievers to himself and restrain evil in this age.

Friends, let us remember that we are distinct from the world, from this passing evil age. We have been called, justified, sanctified, and adopted into God’s family. We are a “a royal priesthood, a holy nation, a people for his own possession, that you may proclaim the excellencies of him who called you out of darkness into his marvelous light” (1 Peter 2:9). Our role in the world is to live coram Deo (before the face of God), not just out of a sense of duty but more deeply from a sense of the new identity that we have in Christ. 

Joel Beeke writes,

Perhaps you call yourself a Christian, but you bend and bow as the winds of culture blow. You do not hunger and thirst for righteousness, but long just to fit in, and so you change your colors like a chameleon. Saltiness requires us to obey God no matter what other people may think. Matthew Poole, a Puritan, said, "In our Christian course we are not to trouble ourselves with what men say of us, and do unto us, but only to attend to our duty of holiness, and an exemplary life."