Matthew 5:14

“You are the light of the world. A town built on a hill cannot be hidden.”

Where it comes from

From the Sermon on the Mount, right after the Beatitudes. Jesus is speaking to ordinary people, not religious leaders.

What it means

Jesus doesn't say "try to be light" or "be light when you feel like it." He says you are. The only question is whether you'll be covered up. A city on a hill doesn't shout; it simply doesn't hide. That's the whole strategy: live openly, kindly, and honestly, and let people see where the light comes from.