The most unique and distinguishing element of the Dominican Breviary, that sets it apart from the Roman, is the variability in the Office of Compline. And no where is this rich variability more evident than during the seasons of Lent, Passiontide, Paschaltide, Ascensiontide, and throughout the octave of Pentecost, when the hymn, Little Chapter, and responses change substantially.
From the Ist Sunday of Lent through Passion Sunday, the responsory is changes as follows:
In the Office of Sundays and feast days the responsory is:
℟. In peace * I will lie down and sleep comes at once.On all other days, the responsory is:
℟. Into your hands O Lord, * I commend my spirit.The resposory In peace is not repeated and is followed immediately by:
℣. I will give no sleep to my eyes, to my eyelids will give no slumber. - I will lie down and sleep and sleep comes at once. - Glory. ℟. In peace I will like down and sleep comes at once.This is followed immediately by the hymn for Lent:
Christ, qui lux es et dies,
Noctis tenebras detegis
Lucisque lumen crederis,
Lumen beatum praedicans.
Precamur sancta Domine,
Defende nos in hac nocte:
Sit nobis in te requies,
Quietam noctem tribue.
Ne gravis somnus irruat,
Nec hostis nos subripiat,
Nec caro illi consentiens
Nos tibi reos statuat.
Oculi somnum capiant,
Cor ad te semper vigilet:
Dextera tua protegat
Famulos, qui te diligunt.
Defensor noster aspice,
Guberna tuos famulos,
Quos Sanguine nercatus es.
Memento nostril Domine,
In gravi isto corpore:
Qui es defensor animæ,
Adesto nobis Domine.
Præsta Pater omnipotens,
Per Jesum Christum Dominum.
Qui tecum in perpetuum
Regnat cum sancto Spiritu.
You are, O Christ, the light and day
Who chases nightly shades away;
Yourself, the light of light confessed,
Proclaim to us the brightness blest.
O holy Lord, we pray that you
May guard us well this whole night through;
In you, O let us find repose
All peaceful till the night shall close.
Let not dull sleep our spirits quell,
Ward off from us the foe from hell,
Nor let the flesh with him unite
To make us guilty in your site.
Then let our eyes due slumber take,
But hearts to you forever wake;
And may your right arm from above
Shield all who turn to you with love.
O strong Defender, hear our prayer,
Repel our foes and break each snare;
Control your servants, be their guide,
Who for their ransom bled and died.
Remember us, O Lord we pray
In weary body here today;
From every ill the soul defend,
Be with us, Lord, until the end.
Almighty Father, this accord
Through Jesus Christ, your Son, our Lord,
Who, with the Holy Spirit true,
For ever reigns in bliss with you.
The antiphon for the Canticle of Simeon, up until the III Sunday of Lent exclusive, is:
Ant. Watch over us, eternal Savior, that the wily tempter may not lay hold on us, for you have been made our helper for evermore.
This venerable hymn is yet one more artifact of that ancient Roman Office that is the basis of the Dominican Office. In 2012, Henri Adam de Villiers penned a short but erudite article over at New Liturgical Movement on the history of this hymn. Here is an excerpt:
...this Compline hymn was kept by many diocesan or religious uses and rites (e.g. Sarum, Worcester, Paris, Cambrai, Tours, Utrecht, Tongeren, Salzburg, Aachen, Mainz, Esztergom, Benevento, Dominican, Augustinian, etc.), usually for Lent. This widespread might be explained, in my view, by the antiquity of that hymn. Indeed, Christe qui lux es et dies is already cited in the Rule for the Virgins written around 500 AD by St. Caesarius of Arles, and has already the function of hymn for Compline during the whole year, outside the Easter time (during this time an other hymn is sung: Christe precamur annue). This beautiful hymn has long been attributed to saint Ambrose (cf. Pat. Lat. 17, 1176-1177), unfortunately, its real author remains unknown. The rhythmic construction is however the same as in the hymns of St. Ambrose.
You can read the entire article here.