Christmas is God lighting a candle; and you don't light a candle in a room that's already full of sunlight. You light a candle in a room that's so murky that the candle, when lit, reveals just how bad things really are.
N. T. Wright (2014). “For All God's Worth: True Worship and the Calling of the Church”, p.10, Wm. B. Eerdmans Publishing