“Amen, amen, I say to you, you will see heaven opened and the angels of God ascending and descending on the Son of Man.”
-- Jn 1:47-51
In her liturgy, the Church joins with the angels to adore the thrice-holy God. She invokes their assistance (in the funeral liturgy's In Paradisum deducant te angeli. . .["May the angels lead you into Paradise. . ."]). Moreover, in the "Cherubic Hymn" of the Byzantine Liturgy, she celebrates the memory of certain angels more particularly (St. Michael, St. Gabriel, St. Raphael, and the guardian angels).
-- CCC 335
Art: Tiziano Vecellio, Archangel Gabriel (detail), polyptych of the Resurrection, 1522.