When there's a strategic victory, you will often see soldiers celebrating. Such was the case two thousand years ago when a major incursion was made that lead to an amazing victory.
The incursion was the birth of Jesus Christ. His birth may have been quiet and lowly, but there was a horde, a huge company, of soldiers of the heavenly host present as witnessed by shepherds out in the fields watching their flocks. This was their king and leader commencing his mission to free millions of captives from an evil overlord.
The war was on. It took everything Media Christ had to break the captives free, but eventually a decisive victory belonged to Christ. He has the legal title to the people who are enslaved and the territory that was occupied by the enemy, and he will one day return with the army of heaven to lock up the evil overlord and fully establish his Kingdom here on earth.
How do I know it was heavenly soldiers that announced his coming to the shepherds? Look at the original language in Luke 2:12-14.
12 And this will be a sign for you: You will find a baby wrapped in strips of cloth and lying in a feeding trough.”
13 Suddenly, a multitude of the Heavenly Army appeared with the angel, praising God by saying,
14 “Glory to God in the highest, and peace on earth to people who enjoy his favor!”
That word ARMY in the original language is στρατία α.
an army, band of soldiersin the NT, the hosts of heaventroops of angelsthe heavenly bodies, stars of heaven (so called on account of their number and their order)
Origin: from a derivative of stratos (an army from the base of G4766, as encamped)
TDNT entry: 18:41,1
Part(s) of speech: Noun Feminine
Strong's Definition: Feminine of a derivative of στρατός stratos (anarmy ; from the base ofG4766, as encamped);camp likeness, that is, anarmy, that is, (figuratively) the angels, the celestial luminaries: - host.