The “O Antiphons”, are Magnificat antiphons used at Vespers of the last seven days of Advent in Western Christian traditions. They are also used as the alleluia verses on the same days in the  Mass. The Cathodic Church has been singing the “O Antiphons” since at least the eighth century.   They are referred to as the “O Antiphons” because the title of each one begins with the interjection “O”. Each antiphon is a name of Christ, one of his attributes mentioned in Scripture. They are:

December 17: O Sapientia (O Wisdom)
“O Sapientia, quae ex ore Altissimi prodiisti,attingens a fine usque ad finem,fortiter suaviterque disponens omnia:veni ad docendum nos viam prudentiae.“
“O Wisdom, coming forth from the mouth of the Most High,reaching from one end to the other,mightily and sweetly ordering all things:Come and teach us the way of prudence.“

December 18: O Adonai (O Lord)
“O Adonai, et Dux domus Israel, qui Moysi in igne flammae rubi apparuisti,et ei in Sina legem dedisti:veni ad redimendum nos in brachio extento.“
“O Adonai, and leader of the House of Israel,who appeared to Moses in the fire of the burning bush and gave him the law on Sinai: Come and redeem us with an outstretched arm.

December 19: O Radix Jesse (O Root of Jesse)
“O Radix Jesse, qui stas in signum populorum,super quem continebunt reges os suum,quem Gentes deprecabuntur:veni ad liberandum nos, jam noli tardare.”
“O Root of Jesse, standing as a sign among the peoples; before you kings will shut their mouths,to you the nations will make their prayer:Come and deliver us, and delay no longer.”

December 20: O Clavis David (O Key of David)
“O Clavis David, et sceptrum domus Israel; qui aperis, et nemo claudit; claudis, et nemo aperit:veni, et educ vinctum de domo carceris,sedentem in tenebris, et umbra mortis.”
“O Key of David and sceptre of the House of Israel;you open and no one can shut;you shut and no one can open:Come and lead the prisoners from the prison house,those who dwell in darkness and the shadow of death.”

December 21: O Oriens (O Dayspring)
“O Oriens, splendor lucis aeternae, et sol justitiae: veni, et illumina sedentes in tenebris, et umbra mortis.
“O Morning Star,splendour of light eternal and sun of righteousness:Come and enlighten those who dwell in darkness and the shadow of death.”

December 22: O Rex Gentium (O King of the nations)
“O Rex Gentium, et desideratus earum,lapisque angularis, qui facis utraque unum:veni, et salva hominem,quem de limo formasti.”
“O King of the nations, and their desire, the cornerstone making both one: Come and save the human race,which you fashioned from clay.”

December 23: O Emmanuel (O With Us is God)
“O Emmanuel, Rex et legifer noster,exspectatio Gentium, et Salvator earum:veni ad salvandum nos, Domine, Deus noster.”
“O Emmanuel, our king and our lawgiver,the hope of the nations and their Saviour:Come and save us, O Lord our God.“