A teaching of Jesus' during The Sermon on the Mount
This teaching is one that I find quite obscure. Jesus tells us that "If the light in you is in darkness, how terribly dark it will be"
To me, Jesus is saying "If you can see the good in the world, you will be full of happiness"
It's easy to go through a day focussed on a single thing and not recognise that there are wonderful things happening outside of my tunnel vision. Sometimes when I'm walking home, or when I'm out with friends I will suddenly notice something (usually plantlife) that makes me joyful inside. My friends may wonder why I've suddenly got a contented, happy look on my face.
I'm happiest when I glow from the light in the world.