Light can be used to describe many things, like a person's personality, overall goodness, or as a state of mind. Light is what exists, what will exist and what always has existed, and nothing can change that no mater how hard someone tries. People can try to remove the light from their being, but none can trully do it. No matter how dark a person's outwardly appearence, the light will always be there deep within that persons very soul. Shrouded be darkness, it will still shine bright, waiting for it's time to rise again. For the truth is that darkness cannot exist without light. They are like two sides of a coin, coexisting with one another. Sure one side may overpower the other at times, but that side cannot be completely consumed. So can be said for the human heart... no matter how much a person grieves and hurts, and no matter how empty that persons life feels, the light will still remain, deep within that persons heart as hope, and will wait in patience until it is called uppon to return to the surface.
When the light returns, all of those feelings of pain and anguish will be replaced with feelings of joy and remorse. That persons life will once again be filled with the happiness he felt long ago.