In Luke 1 Gabriel appears first to Zechariah to announce the coming birth of John the Baptist and then to Mary to announce that she will bear "the son of the most high." He is thus in virtually every Annunciation image and also in images of Zechariah's experience
In early portraits Gabriel is usually dressed as an imperial official and is paired with Michael in flanking a throned figure or sacred space. Weitzmann explains that in the earliest images an archangel would be holding a globe, but "after iconoclasm the globe was sometimes replaced by an icon of Christ in the form of a clipeus" (a shield).1 In addition to the globe or clipeus they will usually be holding a staff, a sceptre, or a labarum (a military standard with a short cloth and topped by a chi-rho). Like all angels, they are pictured as young men without beards.
By tradition Gabriel is classified as an "archangel." In Luke the word is simply "angel," and in the rest of the New Testament only Michael is called an archangel. In the Old Testament Gabriel appears only in Daniel, where he is called a "man" though he is clearly a messenger from God. His ranking as archangel arises from the Book of Enoch, which numbers him several times among the four chief angels, along with Michael, Raphael, and Phanuel. Enoch 70:4 refers to Michael as "one of the archangels," and on this hint Christians came to refer to all four by that honorific. 2
Prepared in 2016 by Richard Stracke, Emeritus Professor of English, Augusta University