Lights are a big part of Christmas celebration, from a modest Christmas tree tucked into a corner of a room to a dazzling display where a light has been put in every conceivable place.  I can’t think of a more appropriate way to emphasize that the Light has come into the world.  Look at a few biblical examples:

 4 In him was life, and the life was the light of men. 5 The light shines in the darkness, and the darkness has not overcome it...9 The true light, which gives light to everyone, was coming into the world.  John 1:4,5,9

12 Again Jesus spoke to them, saying, “I am the light of the world. Whoever follows me will not walk in darkness, but will have the light of life.”  John 8:12

46 I have come into the world as light, so that whoever believes in me may not remain in darkness. John 12:46