O Adonai

O Adonái et Dux domus Israël, qui Móysi in igne flammæ rubi apparúisti, et ei in Sina legem dedísti: veni ad rediméndum nos in brácchio exténto.

O Adonai, and Ruler of the house of Israel, who didst appear unto Moses in the burning bush, and gavest him the law in Sinai; come, to redeem us with an outstretched arm! 

The 'O Adonai' stanza from 'O Come, O Come Emanuel':

Veni, veni Adonai! 
Qui populo in Sinai
Legem dedisti vertice,
In maiestate gloriae.

Gaude, gaude, Emmanuel
nascetur pro te, Israel.

O come, Adonai, Lord of might,
Who to Thy tribes, on Sinai's height,
In ancient times didst give the law
In cloud and majesty and awe.

Rejoice! Rejoice! Emmanuel
Shall come to thee, O Israel.

The following is from the New Liturgical Movement

The medieval use of Augsburg in Germany contains a particularly interesting enrichment of the liturgy on these days. Each O is accompanied by a special chapter, and a special concluding oration, both of which refer back to it; these form a kind of scriptural and euchological commentary on the much older antiphons. Like many medieval uses, that of Augsburg also added other antiphons to the series, which I will note in another post next week; here are the chapters and prayers which go with the seven oldest antiphons, those found in the Roman Breviary. At Augsburg, the Os began on December 13th, and so I have noted them here.

December 14 (18 in the Roman Breviary)

Capitulum Ecce Deus noster: ecce Domi- nus Deus in fortitudine veniet, et brachium ejus dominabitur: ecce merces ejus cum eo, et opus illius coram illo.	The Chapter Behold our God: behold the Lord God shall come with strength, and his arm shall rule: Behold his re- ward is with him, and his work is before him. (Isaiah 40, 9-10)
Aña O Adonai, * et Dux domus Israël, qui Moysi in igne flam- mae rubi apparuisti, et ei in Si- na legem dedisti: veni ad redi- mendum nos in brachio exten- to.	Aña O Adonai, * and leader of the house of Israel, who didst ap- pear to Moses in the fire of the burning bush, and gavest him the Law on Sinai; come thou to redeem us with arm outstretched.
Oratio Deus, qui hominem de lapsu in mortem Unigeniti tui adventu redimisti: praesta, quaesumus; ut qui ejus gloriosam fatentur Incarnationem, ipsius Redemp- toris consortia mereantur: Qui tecum.	The Prayer God, who didst redeem man from the fall unto death by the coming of Thy Only begotten Son; grant, we beseech Thee, that they who confess His glorious Incarnation may merit the fellowship of that very Redeemer; who liveth and reigneth with Thee...