The shepherds heard the announcement of King Jesus from angels.  The angels point to One who is superior to them.  “Having become as much superior to angels as the name he has inherited is more excellent than theirs” Hebrews 1:4 (ESV).  The Son of God is Lord over the angels, but became lower than angels in order to liberate the world from the forces of sin and death.  By His own death He defeated our true enemies.  He is now putting all things under His feet.  Angels, and all creation, bow before the Triumphant Son.

For it was not to angels that God subjected the world to come, of which we are speaking.  It has been testified somewhere, “What is man, that you are mindful of him, or the son of man, that you care for him? You made him for a little while lower than the angels; you have crowned him with glory and honor, putting everything in subjection under his feet.” Now in putting everything in subjection to him, he left nothing outside his control. At present, we do not yet see everything in subjection to him. But we see him who for a little while was made lower than the angels, namely Jesus, crowned with glory and honor because of the suffering of death, so that by the grace of God he might taste death for everyone. Hebrews 2:5-9 (ESV)