The fourth of seven Great “O” Antiphons of the liturgy, that date back to the seventh or eighth century. These antiphons are chanted or recited at Vespers, or Evening Prayer, the Antiphon before the Magnificat. They are also the Alleluia verse at the Mass.
O CLAVIS DAVID KEY OF DAVID O Key of David, Scepter of the House of Israel, controlling at your will the gate of Heaven who opens and no man shuts, who shuts and no man opens
R :Come, and bring forth the captive from his prison, he who sits in darkness and in the shadow of death. Isaiah 22:22. Symbols: key; broken chains
Benedictine monks arranged these antiphons with a definite purpose. If one starts with the last title and takes the first letter of each one — Emmanuel, Rex, Oriens, Clavis, Radix, Adonai, Sapientia — the Latin words ero cras are formed, meaning, “Tomorrow, I will come.” In these words, the Lord Jesus, for whose coming we prepare in Advent and to whom we address these seven Messianic titles, now speaks to us. The O Antiphons not only bring intensity to our Advent preparations, but they bring our preparations to a joyful conclusion. Each antiphon begins with “O” and include a different Scriptural image through the Old Testament, all imploring the Messiah to come. As Elsa Chaney in Twelve Days of Christmas states, “They seem to sum up all our Advent longing as they paint in vivid terms the wretched condition of mankind and his need of a Savior.”