A critical component of light is energy. If there was nothing energizing the light, there would be no light. The command of Christ, Let Your Light Shine, is exactly the same way.
Christ says that we as believers are the “light of the world.” But, without Christ being the very source of our life, we will not have the ability to shine His light. This is why being diligent to take time developing a personal relationship with the Lord is so vital. God not only becomes the very source of our life, He also displays His life through us. It is this life that shines His light for others to see, drawing them to Himself.
The opposite is also true. Trying to imitate God’s light without Him as the very source of that light is actually a counterfeit. This is a facade and will not stand the test of time. It is only by abiding in the light, as He is in light, that we are able to be the light.