Jesus:
I am the Light of the world.
I am not only the cause of visible light, but I am the Light of Goodness, Justice, Integrity, Peace, Joy, Wisdom and anything good that you can think of. This invisible light is my Presence, and this is what I call you to bear in your heart.
So when I say you are the Light of the world, I am saying that you have to fill your self with my goodness and that you have to shine in your good works my Presence to others.
You have to be a living torch, a beacon of light, a bearer of my Light; you must reflect me to the world. Shine my dear child and I assure you that your Light will never die out, but will shine for eternity.