Philippians 2:15 "... you shine as lights in the world."
I look up at the stars at night, I am impressed by the number of them, the designs they make in the sky, knowing that each one is like our own sun. But along with those dots of light is a great deal of darkness. Paul sees the darkness as the world, an evil, bleak space, that thoroughly rejects God and all he has to offer. But in the midst of that dark space there are dots of light.
We live among people who do not know God. But here we are - like "stars in the universe" as one translation puts it. We, as believers, will stand out in a dark and depressive world that has rejected Jesus Christ.