The Sermon on the Mount is dense with theological substance and homiletical potential. Last week we read Jesus’ redefinition of what it means to be blessed. This week we pick up where we left off with a text that could easily fill at least two (and maybe three) different sermons. In the first half (13-16), Jesus addresses the identity of His followers and how their identity impacts the world around them. The second half (17-20) is an account of Jesus’ relationship to and fulfillment of the Law. While it would be possible to treat the whole text (in a really long sermon), it is probably better to choose only part of this reading.

I would suggest limiting yourself to the first half. Even within this section, you might limit yourself further. In these verses, Jesus describes His followers using the metaphors of salt (verse 13) and light (verses 14-16). He uses them to make the same point, but it might help your hearers to choose one metaphor and stick with it throughout the sermon.

“Nothing is more useful than salt and sunshine,” said Pliny.[1] The importance of light is obvious and the metaphor is common throughout the Scriptures (see, for example, Isaiah 2, 9, 42, and 60 and John 1, 3, 8, and 12). The importance of salt, however, is probably less familiar to contemporary hearers and may need explanation. Commentaries list many uses of salt, both ancient and modern. Salt preserves, flavors, tenderizes, and cleanses. It is used in pottery, fertilizing, and bleaching. It softens water and melts ice.

It is this last use which stood out to me when I was a pastor in Minnesota. I preached on this text one year shortly after an ice storm. The walkway from the parking lot to the church was coated with more than an inch of ice, making the slight incline to the front door almost impossible to ascend. Later that day, as I was reflecting on the usefulness of salt at my desk, I noticed a big black truck roll into the parking lot. It was a truck I had seen before. It belonged to one of our members. I watched him get out and walk gingerly to the back of his ,. He pulled out a bag and began sprinkling salt up and down the walkway. Then, a few minutes later, he pulled out a shovel and began chipping away at the ice. Little by the little, the impassible sheet of ice gave way and the path to church was clear. It struck me as I walked to my car in the evening how useful salt is, indeed.

This seems to be Jesus’ point. Both salt and light are useful, helpful, even essential. The world needs salt and light. The same goes for Jesus’ followers. The world needs them. They are useful, helpful, even essential. Or, at least, they should be.

In these verses, Jesus notes problems that arise when salt and light are not being themselves. When salt loses its saltiness, how will the world be salted?[2] When a lamp is not shining, how will the people in the house see? They have a function to perform. They have been designed for a purpose.

Likewise, the followers of Jesus have a function to perform. When they do not perform it—that is, when they are not being themselves—the world suffers.

What is this function? In short, their job is to perform good works (“…so that they may see your good works…”), not for themselves, but for the benefit of others and to the glory of God (“…and give glory to your Father who is in Heaven”). Here it would be appropriate to call your hearers toward a life of good and God-honoring works.[3] Which works might you encourage? It would help to be concrete and give some examples. You have several options for where to find them.

  • You could pick up on either the salt or light metaphor and encourage them to “break up the ice” in relationships with others, or “light the way” for those who are stumbling in the darkness.
  • You could look ahead in the Sermon on the Mount and encourage them toward the types of works Jesus named for the people of His day.
  • You could choose some specific works which arise from within the congregation and its context.

The purpose of these good works has nothing to do with our standing before God, of course. They do not benefit us in the least, but they are no less important. They serve a world in need of help and give glory to the Father. When we do what we were made to do, we honor the One who made us.

To this point, I have not given you much good news to proclaim. As encouraging as it may be to hear we are useful, this still is not the promise of God in Christ. In order to proclaim the promise, you will have to look to the indicatives. “You ARE the salt of the earth… You ARE the light of the world.” That is identity-language and therein lies the promise. In Christ, God gives us our identity. He speaks what we ARE, and that is what we become: Forgiven. Restored. His children. His people. Blessed.

Proclaim this promise to your hearers and encourage them to be what God calls them.


Additional Resources:

Concordia Theology-Various helps from Concordia Seminary in St. Louis, MO to assist you in preaching Matthew 5:13-20.

Text Week-A treasury of resources from various traditions to help you preach Matthew 5:13-20.

Lectionary Podcasts-Dr. David P. Scaer of Concordia Theological Seminary in Ft. Wayne, IN walks us through Matthew 5:13-20.