Praying the “O Antiphons” in Advent

Traditionally the Church prays the “O Antiphons” from December 17 through December 23, in the Evening Prayer (Vespers) of the Liturgy of the Hours, before and after the Magnificat. Each of these prayers begins with the word “O” – thus the name – and highlights one of the prophetic titles given to the Messiah taken from the book of Isaiah.