[Officium]
Dominica Sanctissimae Trinitatis

[Ant Vespera]
Glory be to thee, O equal Trinity * one Deity, from before all ages, so now and for evermore.
Praise and endless glory be * to God the Father, the Son, and the Holy Paraclete, for ever and ever.
Let the glory of praise * be heard from the mouth of all to the Father, and to the begotten Son; let it equally resound with perpetual praise to the Holy Spirit.
Praise be to God the Father, * and to his co-equal Son, and to thee, O Holy Ghost: with perpetual delight may it resound from our lips for ever.
From whom are all things, * through whom are all things, and in whom are all things: to him be glory for evermore.

[Hymnus Vespera]
v. As fades the glowing orb of day, 
To thee, great source of light, we pray;
Blest Three in One, to every heart 
Thy beams of life and love impart.
_
At early dawn, at close of day,
To thee our vows we humbly pay;
May we, mid joys that never end,
With thy bright saints in homage bend.
_
To God the Father, and the Son,
And Holy Spirit, Three in One,
Be endless glory, as before
The world began, so evermore.
Amen.

[HymnusM Vespera]
v. O Trinity of blessed Light,
O Unity of sovereign might,
as now the fiery sun departs,
shed Thou Thy beams within our hearts.
_
To Thee our morning song of praise,
to Thee our evening prayer we raise;
Thee may our glory evermore
in lowly reverence adore.
_
All laud to God the Father be;
all praise, Eternal Son, to Thee;
all glory, as is ever meet,
to God the Holy Paraclete. 
Amen.

[Versum 1]
V. Bless we the Father, and the Son, and the Holy Ghost.
R. Let us praise Him and exalt Him above all for ever.

[Ant 1]
Thanks be * to thee, O God, thanks be unto thee, O True and One Trinity, O one almighty Deity, Holy and One Unity.

[Oratio]
Almighty and everlasting God, you have given thy servants in the confession of the true faith, to acknowledge the glory of the Eternal Trinity, and to adore the unity in the power of thy Majesty; grant, that by steadfastness in this faith we may ever be defended from all adversities.
$Per Dominum

[OratioW]
O God, the Strength of all them that put their trust in thee, mercifully accept our prayers, and because through the weakness of our mortal nature we can do no good thing without thee, grant us the help of thy grace, that in keeping of thy commandments we may please thee, both in will and deed.
$Per Dominum

[Commemoratio 1]
!Commemoratio Dominica I post Pentecostem
Ant. Speak, Lord, for thy servant heareth.
_
V. Let the evening prayer ascend unto thee, O Lord.
R. And let there descend upon us thy mercy.
_
$Oremus.
O God, the Strength of all them that put their trust in thee, mercifully accept our prayers, and because through the weakness of our mortal nature we can do no good thing without thee, grant us the help of thy grace, that in keeping of thy commandments we may please thee, both in will and deed.
$Per Dominum

[Invit]
The True God is Unity in Trinity, and Trinity in Unity. * O come, let us worship.

[Hymnus Matutinum]
v. O God, by whose command is swayed
This ordered world which thou hast made;
Parent of heavenly clemency,
In nature One, in persons Three;
_
Assist us while our minds we raise,
Inflamed with thy immortal praise;
That with our sober thoughts, we may
Forever our thanksgiving pay.
_
May age by age thy wonders tell,
Eternal praise thy works reveal,
And sing with the celestial host
The Father, Son, and Holy Ghost.
Amen.

[Ant Matutinum]
Be present, O One Almighty God, * Father, Son, and Holy Ghost.;;8
We acknowledge that Thou art One in Being, * and Three in Persons.;;18
We testify * that thy Being, thy Life, and thine Understanding are One and eternally unchangeable.;;23
Upon thee do we call, * thee do we praise, thee do we worship, O Blessed Trinity.;;46
Thou art our Hope, * Thou art our Salvation, Thou art our glory, O Blessed Trinity.;;47
Be Thou our Deliverer, * our Saviour, our Life-giver, O Blessed Trinity.;;71
The Father is Love; * the Son is Grace; the Holy Ghost is Communion. Blessed be the Trinity.;;95
The Father is Truth; * the Son is Truth; the Holy Ghost is Truth. Blessed be the Trinity.;;96
The Being of the Father, * and of the Son, and of the Holy Ghost, is one. Blessed be the Trinity.;;97

[Nocturn 2 Versum]
V. Blessed art Thou, O Lord, in the firmament of heaven.
R. And above all to be praised and glorified for ever.

[Nocturn 3 Versum]
V. By the Word of the Lord were the heavens made.
R. And all the host of them by the Breath of His mouth.

[Lectio1]
Lesson from the book of Isaias
!Isa 6:1-4
1 In the year that king Ozias died, I saw the Lord sitting upon a throne high and elevated: and his train filled the temple.
2 Upon it stood the seraphims: the one had six wings, and the other had six wings: with two they covered his face, and with two they covered his feet, and with two they hew.
3 And they cried one to another, and said: Holy, holy, holy, the Lord God of hosts, all the earth is full of his glory.
4 And the lintels of the doors were moved at the voice of him that cried, and the house was filled with smoke.

[Responsory1]
R. I saw the Lord sitting upon a throne, high and lifted up, and the whole earth was full of His glory;
* And His train filled the temple.
V. Above it stood the Seraphim each one had six wings.
R. And His train filled the temple.

[Lectio2]
!Isa 6:5-8
5 And I said: Woe is me, because I have held my peace; because I am a man of unclean lips, and I dwell in the midst of a people that hath unclean lips, and I have seen with my eyes the King the Lord of hosts.
6 And one of the seraphims flew to me, and in his hand was a live coal, which he had taken with the tongs off the altar.
7 And he touched my mouth, and said: Behold this hath touched thy lips, and thy iniquities shall be taken away, and thy sin shall be cleansed.
8 And I heard the voice of the Lord, saying: Whom shall I send? and who shall go for us? And I said: Lo, here am I, send me.

[Responsory2]
R. Blessed be the Lord God of hosts, Who only doeth wondrous things.
* And blessed be His glorious Name for ever.
V. And let the whole earth be filled with His glory. Amen. Amen.
R. And blessed be His glorious Name for ever.

[Lectio3]
!Isa 6:9-12
9 And he said: Go, and thou shalt say to this people: Hearing, hear, and understand not: and see the vision, and know it not.
10 Blind the heart of this people, and make their ears heavy, and shut their eyes: lest they see with their eyes, and hear with their ears, and understand with their heart, and be converted and I heal them.
11 And I said: How long, O Lord? And he said: Until the cities be wasted without inhabitant, and the houses without man, and the land shall be left desolate.
12 And the Lord shall remove men far away, and she shall be multiplied that was left in the midst of the earth.

[Responsory3]
R. Let God, even our own God, bless us; let God bless us.
* And let all the ends of the earth fear Him.
V. God be merciful unto us, and bless us.
R. And let all the ends of the earth fear Him.
&Gloria
R. And let all the ends of the earth fear Him.

[Lectio4]
From the Book on the Faith, addressed to Peter by St. Fulgentius, Bishop [of Ruspa]
!Found in the Works of Augustine, tom. 3
The Faith which the holy Patriarchs and Prophets received from God before His Son was made Flesh, the Faith which the holy Apostles heard from the Lord Himself when Present in the Flesh, the Faith which the same Apostles learnt by the teaching of the Holy Ghost not only to preach by word of mouth, but also to leave behind them in their writings for the healthful instruction of all that should come after, that Faith teacheth that the Trinity, that is to say, the Father, the Son, and the Holy Ghost, is but One God. But we could not truly call the Father, the Son, and the Holy Ghost a Trinity, if One and the Selfsame Person were named Father, Son, and Holy Ghost.

[Responsory4]
R. Who is so great a God as our God?
* Thou art the God that doest wonders.
V. Thou hast declared thy strength among the people Thou hast with thine arm redeemed thy people.
R. Thou art the God that doest wonders.

[Lectio5]
Nor if as the Being of the Father, the Son, and the Holy Ghost is One Being, so were there but One Person, then were it untrue to say that God is a Trinity. On the other hand, if, as the Persons of the Father, the Son, and the Holy Ghost are distinguished One from Another by that which is proper to Each, so were They diverse by difference of nature, then were it untrue to say that God is One. But since concerning the nature of the One True God, Who is a Trinity, it is the Truth to say that God is One, and the Truth to say that God is a Trinity, therefore the True God is a Trinity in Persons, and an Unity in nature.

[Responsory5]
R. To thee be praise, to thee be glory, to thee be thanksgiving for ever and ever,
* O Blessed Trinity.
V. And blessed is thy glorious and Holy Name, and to be praised and exalted above all for ever.
R. O Blessed Trinity.

[Lectio6]
Through this Oneness of nature All That the Father is is in the Son and the Holy Ghost, All That the Son is is in the Father and the Holy Ghost, and All That the Holy Ghost is is in the Father and the Son. Of the Father, the Son, and the Holy Ghost, None is without Other, None is before Other, None is Greater than Other, None is Mightier than Other. The Father, as touching the One Divine Nature, is neither before nor greater than the Son and the Holy Ghost neither is it possible that the Eternity and Infinity of the Son, whether as before or greater, should be before or greater than the Eternity and Infinity of the Spirit.

[Responsory6]
R. Great is the Lord, and greatly to be praised;
* And His Wisdom is unsearchable.
V. Great is our Lord, and of great power, and His understanding is infinite.
R. And His Wisdom is unsearchable.
&Gloria
R. And His Wisdom is unsearchable.

[Lectio7]
From the Holy Gospel according to St. Matthew
!Matt 28:18-20
At that time, Jesus said unto His disciples: All power is given unto Me in heaven and in earth. Go ye, therefore, and teach all nations, baptizing them in the Name of the Father, and of the Son, and of the Holy Ghost. And so on.
_
Homily by St. Gregory of Nazianzus, Patriarch of Constantinople
!Treatise on the Faith
There is no Catholic but knoweth that the Father is a Very Father, the Son a Very Son, and the Holy Ghost a Very Holy Ghost, even as the Lord Himself saith unto His Apostles: “Go ye and baptize all nations in the Name of the Father, and of the Son, and of the Holy Ghost.” This is that Perfect Trinity Who is but One being, and of Whom therefore we testify that His Substance is one. For we make no division in God, as divisions are made in bodies, but we testify, that, according to the power of the Divine Nature, Which standeth not in matter, the Persons named have a real existence, and that God is One.

[Responsory7]
R. Bless we the Father, and the Son, and the Holy Ghost.
* Let us praise and exalt Him above all for ever.
V. Blessed art Thou, O Lord, in the firmament of heaven, and above all to be praised and glorified for ever.
R. Let us praise and exalt Him above all for ever.

[Lectio8] (rubrica 1960)
@:Lectio8a:s/It is.*//s

[Lectio8a]
We do not say, as some have dreamt, that the Begetting of the Son of God is an outgrowing from one part to another part neither do we say that He is the Word in the sense of a mere sound uttered by a voice, but we do believe that these three Names and the Persons meant by them are all of only One Being, One Majesty, and One Power. And therefore we testify that God is one, because this One-ness of His Majesty forbiddeth that we should use the Plural form of speech and say, “Gods.” It is Catholic language to say, “Father and Son,” but we cannot and must not say that the Father and the Son are two gods. And that, not because the Son of God is not by Himself God; yea, He is Very God of Very God but because we know that the Son of God is not from elsewhere, but from the One Father Himself, and therefore we say that God is One. This is the doctrine which Prophets and Apostles have delivered; this is the doctrine which the Lord Himself taught when He said: “I and the Father are One,” (John x. 30,) that is, He meant, as touching the one Divine Being, but as touching Persons, We are distinct.

[Responsory8]
R. One Seraph cried unto another:
* Holy, Holy, Holy is the Lord God of hosts; the whole earth is full of His glory.
V. There are Three That bear record in heaven: the Father, the Word, and the Holy Ghost, and these Three are One.
R. Holy, Holy, Holy is the Lord God of hosts.
&Gloria
R. The whole earth is full of His glory.

[Responsory8] (rubrica cisterciensis)
@Tempora/Pent03-2Feria:Responsory2

[Lectio9]
!Commemoration for the First Sunday after Pentecost
From the Holy Gospel according to Luke
!Luke 6:36-42
At that time: Jesus said unto His disciples Be ye merciful, as your Father also is merciful. And so on.
_
Homily by St. Augustine, Bishop of Hippo
!15th Sermon on Matthew, Words of the Lord
There are two works of mercy which free us, and which the Lord Himself hath briefly named in the Gospel “Forgive, and ye shall be forgiven give, and it shall be given unto you.” “Forgive, and ye shall be forgiven”, such is the promise of pardon. “Give, and it shall be given unto you”, such is the promise of favour. As touching forgiveness thou hast trespasses which thou wouldest fain have forgiven, and them which have trespassed against thee, whom thou canst forgive. As touching favour, there are beggars that beg from thee, and thou art a beggar to God. When we pray, we are all beggars to God, standing at the door of the Great Householder, yea, falling down on our knees, and beseeching Him to give us somewhat and that somewhat is God Himself. What doth a beggar ask of thee Bread. And what dost thou ask of God but that Christ Who saith: “I am the Living Bread Which came down from heaven?” If ye will be forgiven, forgive ye. If ye will be pardoned, pardon ye. If ye will receive, “give, and it shall be given unto you.”
&teDeum

[Lectio9] (rubrica 1960)
@:Lectio8a:s/.*(It is)/$1/
&teDeum

[Capitulum Laudes]
!Rom 11:33
v. O the depth of the riches of the wisdom and of the knowledge of God! How incomprehensible are his judgments, and how unsearchable his ways! 
$Deo gratias

[Hymnus Laudes]
v. O thou, who dost all nature sway,
Dread Trinity in Unity,
Accept the trembling praise we pay
To thy eternal majesty.
_
The star that heralds in the dawn
Is slowly fading in the skies;
The darkness melts; O thou true light,
Upon our darkened souls arise.
_
To God the Father glory be,
And to the sole-begotten Son,
And Holy Ghost co-equally,
While everlasting ages run.
Amen.

[Ant 2]
Blessed be the Holy One * the Maker and Lord of all things. Blessed be the Holy and Undivided Trinity, now and always, and unto unending ages of ages.

[Commemoratio 2]
!Commemoration of the First Sunday after Pentecost
Ant. Be ye therefore merciful, as your Father also is merciful, saith the Lord.
_
V. The Lord reigneth; He is clothed with majesty.
R. The Lord is clothed with strength, and has girded Himself with power.
_
$Oremus
O God, the Strength of all them that put their trust in thee, mercifully accept our prayers, and because through the weakness of our mortal nature we can do no good without thee, grant us the help of thy grace, that in keeping of thy commandments we may please thee, both in will and deed.
$Per Dominum

[Lectio Prima]
!1 John 5:7
v. And there are three who give testimony in heaven, the Father, the Word, and the Holy Ghost. And these three are one.

[Responsory Breve Tertia]
R.br. Bless we the Father, and the Son, * and the Holy Ghost.
R. Bless we the Father, and the Son, * and the Holy Ghost.
V. Let us praise and exalt Him above all for ever.
R. And the Holy Ghost.
&Gloria
R. Bless we the Father, and the Son, * and the Holy Ghost.

[Capitulum Sexta]
!2 Cor 13:13
v. The grace of our Lord Jesus Christ, and the charity of God, and the communication of the Holy Ghost be with you all. Amen.
$Deo gratias

[Responsory Breve Sexta]
R.br. Blessed art Thou, O Lord, * in the firmament of heaven.
R. Blessed art Thou, O Lord, * in the firmament of heaven.
V. And to be praised and glorified for ever.
R. In the firmament of heaven.
&Gloria
R.Blessed art Thou, O Lord, * in the firmament of heaven.

[Responsory Breve Nona]
R.br. By the Word of the Lord * were the heavens made.
R. By the Word of the Lord * were the heavens made.
V. And all the host of them by the Breath of His mouth.
R. Were the heavens made.
&Gloria
R. By the Word of the Lord * were the heavens made.

[Versum Nona]
V. Blessed be the Name of the Lord.
R. From henceforth, now, and for ever.

[Versum 3]
V. Bless we the Father, and the Son, and the Holy Ghost.
R. Let us praise Him and exalt Him above all for ever.

[Ant 3]
With all our heart * and with all our voice do we acknowledge thee, praise thee, and bless thee, O God the Father the Unbegotten, O God the Only-Begotten Son, O God the Holy Ghost the Comforter, One Holy and Undivided Trinity, To thee be glory for ever.

[Commemoratio 3]
!Commemoration of the 1st Sunday after Pentecost
Ant. Judge not, that ye be not judged, for with what judgment ye judge, ye shall be judged, saith the Lord.
_
V. Let my prayer, O Lord, be set forth.
R. As incense before thee.
_
$Oremus.
O God, the Strength of all them that put their trust in thee, mercifully accept our prayers, and because through the weakness of our mortal nature we can do no good thing without thee, grant us the help of thy grace, that in keeping of thy commandments we may please thee, both in will and deed.
$Per Dominum