The source of light, the light of ten-thousand suns, is said to exist within each of us, is each of us, and the way to this light leads through darkness. To reach this light we must dive through the substrata of our conscious mind, through the subconscious where the shadow lies. To reach the Self, we must pass through the great void. This passing through darkness is a common theme in mystic literature including modern mythology such as in Tolkien's stories of The Hobbit and The Lord of the Rings, where the stories' heroes have to pass through deep darkness to reach the treasure they seek. Similarly, it is likely no coincidence that our holidays of light, Hanukkah, Christmas, and Diwali come in the dark time of the year (in the Northern Hemisphere).
So as we celebrate our festivals of light, let these holidays remind us of a greater purpose, a deeper darkness, and an infinite light that awaits within us. Maybe this year, you'll begin the journey to directly experience the light of your True Self. Yoga is a pre-eminent path to dive into and purify the mind to reach this treasure of light.