Catechism of the Catholic Church

From the Incarnation to the Ascension, the life of the Word incarnate is surrounded by the adoration and service of angels. When God "brings the firstborn into the world, he says: Let all God's angels worship him.'" Their song of praise at the birth of Christ has not ceased resounding in the Church's praise: "Glory to God in the highest!" They protect Jesus in his infancy, serve him in the desert, strengthen him in his agony in the garden, when he could have been saved by them from the hands of his enemies as Israel had been. Again, it is the angels who "evangelize" by proclaiming the Good News of Christ's Incarnation and Resurrection. They will be present at Christ's return, which they will announce, to serve at his judgment. (559)