"O Antiphons" for the Week before Christmas, Felix Just, SJ: "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 (Dec. 17-23) in the liturgical prayer of the Church, as Antiphons for the 'Magnificat' sung or recited during Vespers (the Evening Prayer of the Liturgy of the Hours). Since the Second Vatican Council, they have also been adapted (slightly reworded and rearranged) for the 'Alleluia Verse' of the Mass (the short scriptural text or paraphrase that immediately precedes the Gospel reading). Each Antiphon invokes the coming of the Messiah, beginning with a biblical title and closing with a specific petition."
These are the O Antiphons as they are used in the Alleluia verse before the Gospels from December 17 to 23 (or 24?); I've rearranged them to match the order of the Latin acrostic, "Ero cras," "I will return tomorrow."
- O Sapientia
O Wisdom of our God Most High,
guiding creation with power and love:
come to teach us the path of knowledge!
- O Adonai
O Leader of the House of Israel,
giver of the Law to Moses on Sinai:
come to rescue us with your mighty power!
- O Radix Jesse
O Root of Jesse’s stem,
sign of God's love for all his people:
come to save us without delay!
- O Clavis David
O Key of David,
opening the gates of God's eternal Kingdom:
come and free the prisoners of darkness!
- O Oriens
O Radiant Dawn, splendor of eternal light, sun of justice:
come and shine on those who dwell in darkness
and in the shadow of death!
- O Rex Gentium
O King of all nations and keystone of the Church:
come and save man, whom you formed from the dust!
- O Emmanuel
O Emmanuel, our King, and Giver of Law:
come to save us, Lord our God!
The Seven Central Titles
The first letters of the opening words in Latin as traditionally used in Evening Prayer when read backwards spell "Ero cras"--"I will return tomorrow."
- December 17: O Sapientia (O Wisdom)
- December 18: O Adonai (O Lord)
- December 19: O Radix Jesse (O Tree of Jesse)
- December 20: O Clavis David (O Key of David)
- December 21: O Oriens (O Dayspring)
- December 22: O Rex Gentium (O King of the nations)
- December 23: O Emmanuel (O Emmanuel--God is with Us)