There are two ways for light to shine. There is overpowering light. Like the light of highbeams on a road at night. The light of the sun that makes us forget the stars and the rest of the universe even exist. Light so bright it hurts our eyes. Light that can even, ironically, blind us. And although there are a few times in the Bible when Jesus appears as a light like the sun, blazing in glory, those are very rare. We human beings can’t handle the dazzling reality of God’s holiness and glory and power and might.

But on Christmas we celebrate the light. We celebrate the days that follow the darkest day of the year, in eager expectation that more and more light will come each day. We celebrate every instance of good triumphing over evil. But it gets more specific. We celebrate the one who claimed to be “the light of the world.”

Jesus, the light of the world, does not come in blazing glory, bur rather, like a candle, like a star in the night sky, a light that shines in the midst of the darkness, not a light that extinguishes all the darkness, at least not yet. But even though he shines like a candle, we are invited to live in the light. If we choose to live in the light, we are promised two things. One, that darkness will be exposed. And two, that the light will guide our way.

By my reckoning, there are three types of darkness. There’s the darkness of personal moral failing, all the ways in which we wound others and ourselves, all our self-centered desires. It’s darkness that isn’t always easy to see, like a shirt that got a dribble of oil on it. When you look at the shirt in the dim light of your closet, it looks clean. And then you walk into the sunshine and realize that there’s a trail of oil for all the world to see. Jesus’ light exposes the “oil” on our shirt. Sometimes Jesus cleans that oil, those personal moral failings, right up. All of a sudden we no longer struggle with gossip, or anger, or alcohol, or impatience. But sometimes Jesus just exposes that stain for what it is and says, come with me anyway, even if you do have a mess on your shirt, even if you are a sinner, even if you haven’t got your act together.

Then there’s the darkness of the world around us—of war and orphans and poverty and depression and despair. Following Jesus means that we see the darkness, and we are invited to participate in shining light in those dark places, in changing the patterns of injustice.

And finally, there is the darkness of heartache. Of loved ones who have died. Of abandonment. Of natural disaster. Of things entirely out of our control that nevertheless snatch away the light. Jesus offers to shine his gentle light into that darkness too. He promises not to snuff out the smoldering candle, not to extinguish the fire that burns low. But rather to be the light of comfort, of peace, and of hope in that darkness.

So Jesus’ light exposes the darkness for what it is, and sometimes that feels uncomfortable, like walking around with a big stain on your shirt. But Jesus’ light also shows us the way. Light gives us comfort, guidance, reassurance that we are not alone on the path we walk. Light shows us how to walk in the darkness with sure feet, with confidence and purpose. Light draws us home. In this season of Christmas, as we celebrate the light of the world, let us give thanks that he exposes the darkness and invites us to walk in the light.