The angels of the Nativity vs. the demons of the nations
The gods of the pagans were demons, believed the Church Fathers. They were winning their battle for the hearts and minds of the whole world. Until Christmas. That's why the angels sing "Gloria"!
From The Angels and Their Mission by Jean Cardinal Danielou
The Fathers of the Church present the ages which preceded Christ as marking an increase in the power of the demons. The vestiges of a monotheistic revelation, communicated to all men through the ministry of the angels, grow faint with the flourishing of idolatry and devil worship. Even in the one part of the world which God reserved for Himself, the people of Israel, the rising tide of sin continues to mount. The angels to whom the nations were entrusted are powerless to stem the flood of evil. Origin writes, “Before the birth of Christ these angels could be of little use to those entrusted to them and their attempts were not followed by success. … Whenever the Angel of the Egyptians helped the Egyptians, there was hardly a single proselyte who believed in God.” St. John Chrysostom says the same thing: “God set all things in motion through the angels, and nothing was working out well.” Eusebius develops this pessimistic view with greater preciseness. “In such a flood of evil, since the angels who had first been set in charge of the nations could do nothing for their subjects and were able only to look after the rest of creation—being set up over those parts of the world and following absolutely the will of God, the Architect of all things, and yet unable to help stay the fall of mankind because of man’s own free choice of evil—then a grave and all but incurable disease laid hold of all upon earth. The peoples, each in its own way, were driven on by evil spirits and fell into a frightful abyss of vices… . Even the Jewish nation was drawn into their corruption.”...
But in the midst of this desperate situation the Word of God becomes incarnate, in order to come to the aid of His angels. Eusebius continues as follows: “Now, since such great evils had fallen upon the whole of the inhabited earth through the wicked spirits and their leader, since none of the angels was able to prevent these evils, and since the race He loved was wallowing in the depths of iniquity, it was most fitting that the Word of God, the Saviour of all, through the merciful will of the Father’s love for men, should at first send forth short and feeble rays of His own bright light through His Prophet Moses and the other Godlike men who went before him. But since none who came after could bring a remedy against the evils and the activity of the demons continued to increase day by day, the Saviour Himself came to men as their Physician and helped His angels in their work for the salvation of men.”
That is why the angels in charge of the nations welcomed the coming of the Saviour with great happiness. “The Saviour places under His powerful protection no longer only Israel, just and God-minded, nor His own portion, but all the nations of earth who were first apportioned to the many angels and became involved in all manner of ungodliness; to all of them He announces the knowledge and friendship that is to be found in His Father, God … When He was seen by His own angels, who were first set up over the nations, they immediately recognized their Lord coming to their aid and went to Him joyously, to minister to Him. Just as Sacred Scripture says in the Gospel, `The angels drew near and ministered to Him.’ And elsewhere: `There was a multitude of the heavenly host praising God and saying: Glory to God in the highest and on earth peace, good will to men.’ ”
The mystery of the Christmas angels is primarily that of the angels of the nations surrounding the Infant God who has come to the aid of the pagan peoples entrusted to them, for whom they put forth all their labor in vain. But it is not merely that. It is also the mystery of the hosts of angels who descend from heaven with the Word as He becomes incarnate, to surround Him with their adoration and to serve Him as the Lord. St. Hilary gathers the Scriptural references to this truth when he writes: “When [Christ] comes down to assume humanity, a heavenly entourage accompanies Him. When Mary receives the good tidings, when the shepherds see the heavenly assembly and hear their voices, when the devil tempts Him, the angels minister to Him. For, although He came entirely in the form of a slave, nonetheless He acted in the strength of His Father’s majesty, and that is why the heavens bow down when...the Son of God comes down to earth.” Origen has already shown the angels eager to descend with the Word. “When the angels saw the Prince of the heavenly host tarrying among the places of earth, they entered by the way that He had opened, following their Lord… The angels are in the service of your salvation...They say among themselves, ‘If He has put on mortal flesh, how can we remain doing nothing? Come, angels, let us all descend from heaven.’ That is why there was a multitude of the heavenly host praising and glorifying God when Christ was born. Everything is filled with angels.”