In the Sermon on the Mount, Jesus compares His people to a city on a mountain (Matt. 5:14). It is a striking image, the point of which is that such a city, on such a prominent elevation, cannot be hidden. It is conspicuous. It stands out. It can be seen by all.
The application is arresting, immediate, and direct. Christians are manifest, observable, and pronounced. Like salt on a plate of food, or like light shining in a dark place, they are distinct in the way they live and regulate their lives from day to day.
The illustration serves at one and the same time to make a contrast and a comparison. The contrast is that the city is elevated, while those who observe it live elsewhere. The image works because the one reality—the salt, the light, and the city—is the very opposite of the other—the food, the darkness, and the valley.
But there is a point of comparison as well. The city belongs to the same territory as the valley. It is not over the horizon. It is engaged every day in the view of those who dwell nearby. Which is the point, surely, that Jesus is making in His great kingdom message. Christians, by definition, belong to the kingdom of Christ. The primary loyalty of every believer is to Jesus, and His claim on the lives of His people is absolute. He has given them a kingdom (Heb. 12:28) and an inheritance (1 Peter 1:3), as a consequence of which they are citizens of a heavenly world (Phil. 3:20), looking to things that are unseen and eternal (2 Cor. 4:17–18).
Yet, all around them the world changes. Cultural patterns shift. Fashions change, technology advances, science develops, lifestyles evolve. And notwithstanding the fact that His people are not of this world, Jesus specifically says to His Father, “I do not ask that you take them out of the world” (John 17:15).
The situation of the believer presents at least three unique challenges. First, it presents a challenge of faith. The Christian message can never be easily domesticated in the world; since the days of Jesus and the Apostles, there has been no culture that was ready to entertain the message of the crucified and exalted Messiah. To the Jews it was an offense, and to the Greeks it was utter folly (1 Cor. 1:22–23). Modern culture is no less and no more ready to welcome this radical message that demands repentance and faith in God.
To remain conspicuous as a city on a hill requires Christians to grow in their faith, to be able to articulate it and ready to profess it, and to be prepared to give a reason for the hope they have (1 Peter 3:15). It is precisely for that reason that the church is necessary—so that through the preaching of the Word and participation in the sacraments, we will be grounded in the faith we profess.
Second, the changing face of modern culture also presents a challenge of morality to the people of God. If the Sermon on the Mount articulates the parameters of kingdom life, then its ethic is one of righteousness, holiness, and integrity. More than that, it is not a surface ethic that pleases people, but a heart ethic that pleases God.
Interestingly, the issues Christ raises to illustrate this point are the very issues that surface in modern cultures everywhere. Issues of anger, lust, marriage, retaliation, charity, perjury—these are the issues of modern newspaper headlines. Cultures change, but sometimes they change in the way shop windows change, showing what is inside in new ways. Man’s heart is what shapes man’s culture, and changing cultural norms are often only new expressions of old heart problems.
Over against this, Christians are to be morally upright and blameless, living by the ethic of Christ’s kingdom and subject to His lordship. That can present its own unique challenges, but it is surely one of the reasons Christ teaches His people to pray “lead us not into temptation” (Matt. 6:13).
But there is a third challenge: the challenge of affection. One of the great hallmarks of modern culture is its isolationism; people e-mail or Skype to the other side of the world, but they do not know their neighbors. Some of the older folks in my community live for the visit of their home care aides, because they see virtually no one else all day long.
There is a reason that love is at the heart of the Christian ethic: because it is at the heart of redeeming our culture. Christians are to love one another (John 15:12), so the city on the hill ought to be a place of mutual love. But Christians are to love their neighbors, too (Matt. 19:19). More challenging still, perhaps, they are to love their enemies (5:44).
Perhaps in our interaction with the culture around us, these are the great tests of our discipleship, because it was the way of the Master. Ultimately, of course, His culture received Him not. But who can doubt the good that He did for it and in it; or who can question whether He lived what He taught? He was the very embodiment of the city on the hill principle. May we be the same.