God Asks Them to Be the Salt of the Earth, the Light of the World, and a City Set on a Hill

One of the central themes of this year’s Lutheran Sentinel is vocation. Thus it is only fitting that the Sermon on the Mount (Matthew 5–7) should be addressed. The restoration of vocation has some important roots in this famous discourse of our Lord.
Few other sections of God’s Word have received as much ink or variation in interpretation than what Augustine of Hippo (A.D. 354–430) first called the Sermon on the Mount. The common thread of nearly all its different interpretations is that the sermon should be understood as Law. But by the time of Thomas Aquinas (A.D. 1225–1274), Christ’s exposition of the Law contained herein was deemed so rigorous that it was distinguished (evangelical counsels, etc.) from the Ten Commandments and reserved for the so-called “religious vocations,” i.e. monks/nuns and friars/sisters, who alone were deemed capable of achieving its higher spiritual standard. Everyone else, conversely, was merely expected to adhere (form their faith in love) to the lower demands of a muted Ten Commandments to ensure their salvation, all the while knowing that they would still have to spend many years of purification in purgatory.
On the basis of the Sacred Scriptures, Martin Luther (A.D. 1483–1546) challenged this denial of a vocation to the laity, the downgrading of their spiritual character, and above all else the dangerous notion that the Law could actually be kept by anyone. He not only reasserted the spiritual quality of the priesthood of all believers (1 Peter 2:5–9), but he also maintained that the Sermon on the Mount was the proper explanation of the moral law binding on all. Much like Justin Martyr (A.D. 100–165) in the second century, Abraham Calov (A.D. 1612–1686) and others further reminded the church that the sermon’s call to be the salt of the earth, light of the world, and city set on a hill (Matthew 5:13–16) was not limited to the clergy, but pertained to every Christian as well (Philippians 2:15; Luke 14:24–35).¹
With this in mind, the severity of the sermon is rightly intended to drive all man to despair of themselves and their righteousness. But this same truth also drives man to cling to Christ who perfectly fulfilled it and bestows upon us the higher righteousness that alone exceeds that of the scribes and Pharisees (Matthew 5:17–20). After all, we can only reap the wondrous benefits of the Beatitudes (Matthew 5:1–12) by being incorporated in Christ’s body, the church (Romans 6), through Baptism. How else could we who are incapable of the sermon’s perfection (Matthew 5:48) receive the kingdom of heaven, be comforted, inherit the earth, be satisfied, receive mercy, see God, or even be called the sons of God? Christ was perfectly poor in spirit for us. He mourned, hungered, and thirsted for righteousness for us. He alone was truly merciful, pure in heart, and was the peacemaker between God and man.
For this reason, believers are not told to become the salt of the earth, light of the world, and a city set on a hill. Our God-given faith, created and preserved by the Word and Sacraments alone, has already made us so. What a truly magnificent new reality God’s Word is able to unfold! Then when Christ warns us not to let our salt lose its saltiness, He is not suggesting that good works preserve us in the faith any more than He is saying that we are saved by works. We will remain saint and sinner until our full transformation in Christ on the last day. Rather, Christ is calling us to confess God’s Word in both word and deed. An authentic faith is a “living, busy, active, mighty thing” that cannot help but express itself in love (Formula of Concord, SD IV:10). But woe to the faith or the church that has become incapable of expressing itself! They will be all the harder to win back for Christ (Luke 11:24–26).
The sermon should also not be construed as empty moralism. It is a call to authentically confess our faith by our lifestyle, service, and above all else a Law-Gospel witness to others. This call likewise is not a pretext for anarchy in the church. Christ incorporates His clergy and laity into different roles within His body, the church, so that His mission may be organically carried out within the spheres of our integral and complementary vocations and gifts (1 Corinthians 12).
Finally, it must be remembered that the Lutheran Reformation did not restore the sanctity of seemingly ordinary vocations only to suggest that our confessions should only be ordinary. Christ states, “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 5:16). Strive to be the best daughter, father, nurse, businessman, soldier, etc. that you can be. Even if we are the only light left in our town, a single light in the darkness can still be seen for miles around, bringing faith, hope, and love to all who still sit in darkness. Such a confession will never be without the cross. But can the wonders of the Beatitudes yet to be fully realized in us compare with the very best this fallen world has to offer?
Dr. Timothy R. Schmeling is assistant professor of theology and history at Bethany Lutheran College in Mankato, Minnesota.
¹Abraham Calov, I. N. J. Biblia Novi Testamenti Illustrata (Frankfurtam Main: Wustius, 1676), 1:182–83.