The angels appear above the shepherds and declare the birth of the Christ child with this refrain of peace on earth:
And suddenly there was with the angel a multitude of the heavenly host praising God, and saying,
“Glory to God in the highest, and on earth peace, good will toward men.” (Luke 2:13-14)
Peace on earth.
And yet, as It Came Upon a Midnight Clear recounts, since that angelic declaration of peace there has been “two thousand years of wrong.” Why? Because “man, at war with man, hears not the love-song which they bring.”
There is no peace on earth because we don’t hear the love song.
And so the call continues to go out:
“O hush the noise, ye men of strife, and hear the angels sing.” http://experimentaltheology.blogspot.com/2012/12/christmas-carols-as-resistance.html