I am thinking about what that looks like in my life and I feel God gave me a great example. Let us look outside. I don't know what your outside looks like, but here outside my window there is my deck overlooking a massive expanse of sky. I can see the pool, and also a huge green tree right in front of my deck.
Many times I look out there, but each day looks different depending on the weather. Today the sun is shining bright and everything looks bright and cheery like a great painting. The leaves look greener, the sky looks more blue, the pool looks inviting.
But last week, it was pouring rain. The sky was darkened and ominous. The pool looked creepy and uninviting. The tree looked grayed out. Everything looked sad.

All because of the weather. The tree never changed. The sky is still the sky. The pool is the same....the difference is the WEATHER! LIGHT changes everything!
Well this is the difference of the human spirit. Our spirits were dead in sin. Everything was in place....but nothing was alive. But when the Light who is Christ comes shining in through faith in Him....everything becomes exceedingly bright, vibrant, ALIVE!

The best way I can explain it, is to stare outside when it is gloomy and cloudy. Then when the sun shines forth, go outside and feel the difference....we can have that same difference on the inside of us!
Its all about Light in the Heart. Let the Light shine!