Most familiar today from the Advent hymn, “O Come, O Come, Emmanuel,” the seven traditional “O Antiphons” are actually more than a thousand years old. They have long been used at the very end of Advent in the liturgical prayer of the Church, as Antiphons for the “Magnificat”. Since the Second Vatican Council, they have also been adapted for the “Alleluia Verse” of the Mass. Each Antiphon invokes the coming of the Messiah, beginning with a biblical title and closing with a specific petition.
In the traditional arrangement, when viewed from Christmas Eve backward, the first letters of the Latin texts (Emmanuel, Rex, Oriens, Clavis, Radix, Adonai, Sapientia) spell out the phrase ero cras (“I come tomorrow”).
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