From Dom Guéranger's The Liturgical Year.
Prope est jam Dominus: venite, adoremus.
De Isaia Propheta.
Hæc dicit Dominus Deus: Ecce ego mittam in fundamentis Sion lapidem, lapidem probatum, angularem, pretiosum, in fundamento randatum. Qui crediderit, non festinet. Et ponam in pondere judicium, et justitiam in mensura, et subvertet grando spem mendacii, et protectionem aquæ inundabunt. Et delebitur fœdus vestrum cum morte, et pactum vestrum cum inferno non stabit.
The Lord is now nigh; come, let us adore.
From the Prophet Isaias.
Thus saith the Lord God: Behold I will lay a stone in the foundations of Sion, a tried stone, a corner-stone, a precious stone, founded in the foundation. He that believeth, let him not hasten. And I will set judgement in weight, and justice in measure; and hail shall overturn the hope of falsehood, and waters shall overflow its protection. And your league with death shall be abolished, and your covenant with hell shall not stand.
Heavenly Father! Thou art preparing to set in the foundations of Sion a corner-stone, that is tried and solid; and this stone, which is to give firmness to Sion Thy Church, is Thy Incarnate Son. It was prefigured, as Thy apostle assures us, by that rock of the desert, which yielded the abundant and saving stream that quenched the thirst of Thy people. But now Thou art about to give us the reality; it has already come down from heaven, and the hour is fast approaching when Thou wilt lay it in the foundations. O sacred Stone, which makest all one, and givest solidity to the whole structure! By Thee it will come to pass, that there shall be no longer Jew or Gentile, but all nations shall become one family. Men shall no more build on sand, nor set up houses which floods and storms may overturn. The Church shall rise up from the stone which God now sets, and, secure on the great foundation, her summit shall touch the clouds. With all his weakness, and all his fickleness, man will partake of Thy immutability, O divine Stone, if he will but lean on Thee. Woe to him that rejects Thee, for Thou hast said, and Thou art the eternal Truth: 'Whosoever shall fall upon that stone, shall be bruised; and upon whomsoever it shall fall, it will grind him to powder.’ From this twofold evil, O Thou that art chief corner-stone, deliver us, and never permit us to be of the number of those blind men who rejected Thee. Give us grace ever to honour and love Thee as the cause of our strength, and the one sole origin of our solidity: and since Thou hast communicated this Thy quality of the rock to one of Thine apostles, and by him to his successors unto the end of the world, grant us ever to cling to this rock, the holy Roman Church, in union with which all the faithful on the face of the earth are preparing to celebrate the glorious solemnity of Thy coming, O precious and tried Stone! Thou art coming, that Thou mayst destroy the kingdom of falsehood, and break the league which mankind had made with death and hell.
Hymn for Advent
(In the Mozarabic breviary, first Sunday of Advent)
Christi caterva clamitet,
Rerum parenti proximas
Quas esse sentit gratias,
Laudesque promat maximas.
Vatum poli oracula
Perfecit olim tradita,
Cum nos redemit unicus
Factoris orbis Filius.
Verbum profectum, proditum,
Tulit reatum criminum,
Sumensque nostrum pulverem,
Mortis peremit principem.
A matre natus tempore,
Sed sempiternus a Patre,
Duabus in substantiis,
Persona sola est Numinis.
Venit Deus factus homo,
Nitescat ut cultu novo
Renatus in nato Deo,
Factus novus vetus homo.
Natalis hinc ob gaudium,
Ovans trophæo, gentium
Renata plebs per gratiam
Hæc festa præbet annua.
Adventus hic solemnibus
Votis feratur omnibus,
Quos sustinere convenit,
Tanti diei gloriam.
Secundus ut cum coeperit,
Orbemque terror presserit;
Succurrat hæc humillima
Deo Patri sit gloria,
Ejusque soli Filio,
Cum Spiritu Paraclito,
In sempiterna sæcula.
Let all the assembly of Christ’s faithful ones
laud the graces that are nigh,
and sing their highest praises
to their Creator.
When his only begotten Son,
who created this world, redeemed us,
he fulfilled the promises
which the heavensent prophets spoke in the ages past.
The Word having come down from heaven,
and shown himself to men,
took away the punishment due to their sins;
and assuming our nature, though but dust, he vanquished the prince of death.
Born of a Mother in time,
but begotten eternally from the Father,
in the two substances there is but one Person,
that is the Person of the Word.
God has come into this world made man,
that our old man being changed into the new,
we may put on new beauty
by being regenerated in the new-born God.
Let the Gentiles, who have received this new birth of grace,
in gladness and exultation
at the trophy won by the divine Nativity,
keep every year its feast.
Let this coming of Jesus
be celebrated with devout solemnity by all,
who have so just a share
in the glory of this great day.
That so, when the second coming
shall burst upon the world and fill it with fear,
this most humble expression
of our devout celebration of the first may give us confidence.
To God the Father,
and to his only Son,
and to the holy Spirit,
be glory for ever and ever.
Prayer from the Ambrosian Missal
(In the Mass of the sixth Sunday of Advent, Preface).
Vere dignum et justum est, aequum et salutare, nos beatæ semper Virginis Mariæ solemnia celebrare, quæ parvo utero Dominum cœli portavit; et, angelo praenuntiante, Verbum came mortali edidit Salvatorem. Hic est mundi Redemptor, castis conceptus visceribus; clausa ingrediens, et clausa relinquens.
It is truly meet and just, right and available to salvation, that in this holy time wo should celebrate the memory of the ever blessed Virgin Mary, who carried in the narrow inclosure of her womb the Lord of heaven, and who, according as the angel had foretold her, brought forth the Word become our Saviour in our mortal flesh. This is he who is the Redeemer of the world, conceived in a chaste womb, his Mother both then and at his birth remaining ineffably the Virgin.
 1 Cor. x. 4.
 St. Matt. xxi. 44.