“One of these things is not like the others, one of these things just doesn’t belong.” Do you remember this song from Sesame Street? A group of objects would appear on-screen, and we were asked to decipher which one was out of place. The answer was simple, but the ever-patient Bob McGrath would whistle through the jingle, giving our little eyes enough time to spot the difference. A red balloon stuck out in a group of blue balloons, or one shape did not match the others. Even as children staring at grainy 1980s television sets, we knew when something did not fit.

In his letter to the early church, Peter commanded his readers, “be holy in all your conduct” (1 Peter 1:15). They were to cast off the trappings of the prevailing culture and live as sanctified people. Down through the centuries, the instruction remains the same—there is not a corner of your life you get to claim as off-limits to Christ’s purifying work. We should live in such a way that if our marriages, our business practices, or our daily interactions were lined up alongside those of unbelievers, someone could easily find the outlier. And yet, so often, we make it much too hard.

Far too frequently, we take on the customs of a place we do not call home. We play their game to attain power and wealth. We explain away our sin patterns with the same kind of moral equivalency. Our scandals look like their scandals, our arguments sound like theirs. We fight with the same weapons, harnessing the same rage and vitriol. And so the city on a hill fades from view, behind a fog of our own making. The salt loses its saltiness. The light begins to flicker in the shadows. We lose our witness not because we are too different from the outside world, but because we are too similar.

We forget that our citizenship was blood-bought and we start acting like we belong here.

The Christian life is not child’s play; it is for the sober-minded. But the instructions are often simpler than we make them out to be. We are called to be holy. We are a people set apart, exiles commissioned to serve our host home and pursue righteousness so that when our time is up, those who have been watching can spot the difference.

Our otherness is an invitation to a lost and dying world, meant to make them homesick for a place they’ve never been. The salt creates a craving for richer foods, found at a coming feast. The light draws them in, away from the darkness. Our lives are a dispatch from a far country, heralding the good news, “There is something else out there, something better than all of this.” And we show it is better, dear brothers and sisters, by first showing that it is different.