Dearly beloved, today our Savior is born; let us rejoice. Sadness should have no place on the birthday of life. The fear of death has been swallowed up; life brings us joy with the promise of eternal happiness. And so at the birth of our Lord the angels sing in joy: Glory to God in the highest, and they proclaim peace to his people on earth as they see the heavenly Jerusalem being built from all nations of the world. When the angels on high are so exultant at this marvelous work of God's goodness, what joy should it not bring to the lowly hearts of men?
From a sermon by St. Leo the Great, pope