Discipling Teenagers to Be Salt and Light

“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

In the Sermon on the Mount, Jesus calls his disciples the salt of the earth and the light of the world. He doesn’t command them to “be salt” or to “be light.” Instead, he makes a statement of fact about a Christian’s identity. Salt and light are defining characteristics for believers, so it’s essential we help teenagers understand Jesus’ message. Ultimately, the goal of Jesus’ teaching is not merely to inform his students but to transform them by his grace.

Salt-ology 101

When you think of salt, what likely comes to mind is table salt (sodium chloride). Salt seems to make everything taste better. We use sodium chloride to cure or preserve meats and other foods, along with many other no-food related uses.

The Dead Sea, the sixth saltiest body of water on earth, contains many other salts, such as calcium chloride, potassium chloride, and magnesium chloride. In Jesus’ day, salt from the Dead Sea was a valuable commodity. Roman soldiers earned their wages in salt, which is why many earn a salary today. Salt can’t lose its chemical properties. When Jesus talks about salt ‘losing its saltiness or taste,’ he’s most likely referring to salt’s diminished potency when mixed with other substances. 

In Luke 14:34, Jesus says, “Salt is good, but if the salt has lost its taste, how shall its saltiness be restored?” (Sound familiar?) He continues in verse 35: “It is of no use either for the soil or for the manure pile. It is thrown away.” Luke uses the same Greek word for soil that Matthew uses for ‘salt of the earth’ in Matthew 5.

When salt loses usefulness, we throw it away. The statement “you are the salt of the earth,” then, seems most likely to reference salt’s fertilizing properties. Potassium chloride, in particular, provides an essential nutrient for plant growth. 

The phrase “lost its taste” is noteworthy, too. Translated from the Greek word from which we get the word “moron,” it can mean to make tasteless, or to act foolishly. What good is un-salty salt? Salt that doesn’t taste salty is foolish; therefore, to be salt is to live wisely, in the way God has intended. 

Salt for the Soil

True Christians have a positive effect wherever they are found. They are useful for cultivating what is good, true, and beautiful. They play a part in God’s story of redeeming and healing the brokenness of the world. Their ‘saltiness’ can’t be mixed with worldliness, or it will lose effect.  Conversely, more salt leads to greater effect on the soil.

Teenagers who are walking with Jesus need us to give them clear pictures of ‘saltiness’ in their daily lives. Saltiness looks like respecting teachers, picking up trash, or helping a new student find her classroom. When teenagers speak to build up rather than tear down, that is being salt. When they play their best on the team, but aren’t overly angry about their losses, they offer others a savory taste of God’s grace. Salty faith might look like a teenager taking a stand against racism and hatred, bullying, or sexual harassment. Christian teenagers who demonstrate growing respect for their parents or guardians, who faithfully show up for their shifts at work, who look out for the interests of others, all display the kind of saltiness to which Jesus calls those who follow him.

Christians join God in the kingdom work of sowing peace, love, and goodness in the world. Salt promotes the good of the soil into which it is sown. Although Christian teenagers will often stumble and falter, knowing the grace of Jesus will make a difference in how they live. God promises to complete the good work he starts in their lives. This is the greatest news we have to share with teenagers: God is in the business of transforming our lives into something useful and flavorful.

A World in Darkness

In our modern world, we often take the reality of light-on-demand for granted. In Jesus’ age, darkness was everywhere, limiting what you could do and sometimes creating dangerous situations. Without light, you couldn’t see where you were going in the dark. You might trip and fall or be jumped by highway robbers. You couldn’t see to read or write or sew or cook. 

The world without Christ is in darkness. It’s a cold, dangerous place full of disoriented people. Human beings love darkness because we fear having our sin exposed. Jesus is “THE light of the world” (John 8:12, Is. 9:2). He exposes the world in its sin and ugliness. 

Light also reveals what is good and true. Light shows us where the road is on a dark night. It keeps us safe. Christians reflect the nature of Jesus, the light of the world.

Teenagers recieve a vast array of lies in our culture. They hear lies of self: self-making, self-belief, self-love, self-help. These contain slivers of truth  (it’s okay to love yourself, care for yourself, and have self-confidence), but are corrupted with falsehood.

Jesus doesn’t say, “be who you want to be.” He says, “be who I made you to be.” Jesus doesn’t say “believe in yourself.” He says, “believe in me.” Jesus doesn’t say, “love yourself above all.”  He says, “deny yourself, love God, and love your neighbor as yourself.”  Jesus doesn’t say, “help yourself.” He says, “I have come to seek and save the lost.” 

Teenagers also hear many lies about God: “God is whatever I think him to be.” And perhaps, “because evil exists, God can either be good or all powerful, but not both.” Or even, “All religions are equally valid, and Jesus isn’t the only way to God.”

They hear lies about nature: “This material world is all there is.” Or “we are products of chance.” Or “there is no life after death.” 

Christians expose darkness and lies, revealing what is good and right.

Light for the World

Believers bring light to a dark and hopeless world. Jesus says his disciples are to let their light shine before others. The light must not be hidden. Just as salt must contact soil, so the light must shine in the darkness. We are to put our light on a stand, not under a basket. Wherever God has placed them, believers are to shine the light of the gospel through words and deeds that glorify God.

Being light means displaying the glory of God through good works motivated by God’s grace. God calls us to speak and live the truth. Our actions and words must be in alignment as followers of Christ. If we say that Jesus saves sinners, we must live in humble acknowledgement of our own status as sinners. Because we believe that Jesus is the only way to God, we must demonstrate care and concern for the lost through evangelism. If we say heaven is our home and Christ is our king, we must avoid enslavement to an earthly lust for money, sex, or power. We shouldn’t climb over others to get ahead or despise the poor or the powerless, but care for them as those who Christ came specifically to seek and save. 

Jesus is on a mission to redeem the world from death and darkness. God has brought us from darkness into his glorious light, making us new. As those who belong to him, he calls us and our teenagers to shine the light of his gospel in the darkness of the world. 

Parents and youth workers have the privilege and responsibility of modeling for teenagers this world-transforming life of faith, inviting them to join in Christ’s mission to make all things new. Thankfully, God has given us his all sufficient grace to pardon every failing, and empower every act of goodness and love for his own glory.   

Join us November 2-4 for Rooted 2023 in Nashville, where we’ll explore the Sermon on the Mount together. How can we find true human flourishing? The world we disciple our teenagers in today does not merely offer them an alternative way to live, but an alternative account of where true human flourishing is found. This competing vision encompasses all that we believe about ourselves, our bodies, justice, security, suffering, and meaning. In the most famous sermon in human history and the longest recorded teaching from Jesus’ ministry, our Lord gives us a wholistic vision of how we can live in a way that leads to our flourishing in every aspect of our lives. At the core, his teaching shows us that such flourishing is only found through faith in the God who created us and in Jesus Christ who is redeeming us. As we walk through the Sermon on the Mount together, our prayer is that the teachings of Jesus will invert and subvert the teachings of this world and compel our hearts to live in light of the Kingdom of God in faith.

Logan is the Associate Pastor at The Evangelical Free Church of Mt. Morris in northwest Illinois, where he lives with his wife Michelle and two children, John and Eliana. Logan graduated with an MDiv from Trinity Evangelical Divinity School and is passionate about gospel-centered ministry in local churches. In his spare time, he enjoys playing music with his wife, spending time outdoors, and roasting and drinking specialty coffee.

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