In the Church’s Liturgy of the Hours, Evening Prayer, also know as Vespers, always includes the great prayer of Mary known as the Magnificat. Each day, the Magnificat is preceded by a short verse or “antiphon.”

In the last seven days of Advent (December 17-24), the antiphons before the Magnificat are known as the “O Antiphons.

These “O Antiphons” were composed in the seventh or eighth century when monks put together texts from the Old Testament, particularly from the prophet Isaiah, which looked forward to the coming of our salvation

Each of the O Antiphons highlights a different title for the Messiah: O Sapientia (O Wisdom), O Adonai (O Lord), O Radix Jesse (O Root of Jesse), O Clavis David (O Key of David), O Oriens (O Rising Sun), O Rex Gentium (O King of the Nations), and O Emmanuel.

Each one of them refers to the prophecy of Isaiah of the coming of the Messiah. A feature of the O Antiphons is that the first letter of each invocation, when read backwards, forms an acrostic in Latin: the first letters of Sapientia, Adonai, Radix, Clavis, Oriens, Rex, and Emmanuel in reverse form the Latin words: ERO CRAS. These can be understood as the words of Christ, responding to his people’s plea, saying “Tomorrow I will be there.”

These antiphons could be recited as a family, whether during grace at meals, in front of the manger scene, or in front of the Christmas tree. (XT3)