The first Christmas carol of history, which determined for all times the inner harmony of Christmas, had no human origins—Saint Luke records it as the song of the angels who were the evangelists of the holy night: Glory to God in the highest, and peace on earth among men, those with whom he is pleased, those of good will. This song sets a standard; it helps us understand what Christmas is all about. It contains the key word, which, in our time especially, commands people’s interest more than just about anything else: peace. The biblical term shalom, which is usually so translated, implies much more than the absence of armed conflict; it means the right order of human affairs, well-being—a world where trust and friendship prevail, where neither fear nor want nor treachery nor dishonesty is found. Yet the song of the angels first lays down a precondition, without which there can be no lasting peace: God’s glory. This is the message of peace at Bethlehem: peace among men results from God’s glory. Those who are concerned about the human race and its well-being have to be concerned about God’s glory first of all. God’s glory is not some private concern, left to the personal choice of the individual; it is a public affair. It is a common good, and wherever God is not honored among men, there man as well will not remain honorable. The reason why Christmas affects the peace of man lies in this: because it has restored God’s glory among men.
Ratzinger, J. (1992). Co-Workers of the Truth: Meditations for Every Day of the Year. (I. Grassl, Ed., M. F. McCarthy & L. Krauth, Trans.) (pp. 408–409). San Francisco: Ignatius Press.