God's highest glory on Earth is when Peace comes inside of a people who please Him.
That's not my translation of Luke 2:14, but something really close to that might just be what the angels meant when they sang it. For some recent discussions on translating Luke 2:14, go here In my humble opinion, all of humanity has always been invited to find God, engage Him, and seek to please Him. Only one Man was ever successfully able to do so, but He has invited us to share in His success. So, therefore, the night the angels sang near Bethlehem was the night when the seed of that promise broke through.
God longs to see people contain His Life and live at peace together.