"You are the light of the world. A city built on a hill cannot be hidden. No one after lighting a lamp puts it under the bushel basket, but on the lamp stand, and it gives light to all in the house. In the same way, let your light shine before others, so that they may see your good works and give glory to your Father in heaven." [Matthew 5:14-16]
This particular teaching of Jesus appears to be a little at odds with some of his other teachings, for example the first verse of the next chapter. ("Beware of practicing your piety before others in order to be seen by
them; for then you have no reward from your Father in heaven.")
Of course, Jesus talking about slightly different things in each passage. In the first I quoted, I believe Jesus is making sure that we are in the world, shining so as to give light to others. The previous verses are the "you are the salt of the earth" portion of the sermon, which I've always understood to be about giving savor to the wider world. In short, it's a warning to not hole up with people just like us, but to mix it up, spreading our light and savor to a world that can sometimes lack illumination and flavor.
To be the light of the world is not to show people how pious we are.
We who claim to follow Jesus are the lamp he has put on the lamp stand. Living in the resurrection, we may hope to illuminate without showing off. We might bring light without being obnoxious about it. I believe practicing a piety has merit, but it's for us to practice, not to project or force upon other people.
Living in the light of Christ, we can quietly illuminate some dark places. How much better to remember with much humility that if we do this, it the light of Christ and not our own holiness.
The light of Christ!
Thanks be to God!