It is fitting that when Our Lord and Savior came to earth; when He determined to knit His divine nature unconfusedly, unchangeably, indivisibly, inseparably to our human nature; when He did not abhor the virgin’s womb, but deigned for us men and for our salvation to be born in our flesh—it is fitting that the angels gathered together and shouted for joy. For the glorious appearing of our great God and Savior Jesus Christ declared that the union of God and man has been accomplished, that the divide between heaven and earth had been bridged, and that the reign of death in sin was ended. And so what recourse did the angels have, and how else should they have responded except to sing glorious praise to the Father who, by His Spirit, had gifted all men and the whole world with His incarnate Son?
So in splendid song, with glorious chant, and in magnificent hymn the angels praised God. But notice that their praise was not directed to God; rather, it was directed to men. The angels declared the greatness of God not by fawning over Him, but by proclaiming the wonders of His love to those He was determined to save. And they rejoiced and exalted His mercy not by remaining in heaven, but by seeking out men to whom they could sing their glad tidings.