CCC 332 Angels have been present since creation and throughout the history of salvation, announcing this salvation from afar or near and serving the accomplishment of the divine plan: they closed the earthly paradise; protected Lot; saved Hagar and her child; stayed Abraham’s hand; communicated the law by their ministry; led the People of God; announced births and callings; and assisted the prophets, just to cite a few examples.1 Finally, the angel Gabriel announced the birth of the Precursor and that of Jesus himself.2

1 Cf. Job 38:7 (where angels are called “sons of God”); Gen 3:24; 19; 21: 17; 22:11; Acts 7:53; Ex 23:20-23; Judg 13; 6:11-24; Is 6:6; 1 Kings 19:5.
2 Cf. Lk 1:11, 26.