For to us a child is born, to us a son is given, and the government will be on his shoulders. And he will be called Wonderful Counselor, Mighty God, Everlasting Father, Prince of Peace.Isaiah 9:6 (NIV)
The joy of Christmas Day is the comfort in knowing our God came down to earth in human form to become one of us and live and dwell as we do. That one day he would pay the penalty for our sins so that through him and in him we may have everlasting life.
Rejoice, for He is born!