The way to heaven reopened: St Benedict and the Gradual Psalms

William Blake

Today, the final part of this Lenten series on the Gradual Psalms with some comments from St Jerome, and St Bede.

St Jerome

Today we recall the harrowing of hell, when Christ freed the holy souls to enter heaven.  In this light, St Jerome's comments on the Gradual Psalms emphasises the role of Christ in our ascent of Jacob's Ladder:

These gradual psalms...are called songs of ascent because in them we mount step by step to greater heights...Jacob saw a ladder set up on the ground with its top reaching to heaven, and in heaven the Lord was leaning upon it...

 It is very difficult, indeed, to ascend from earth into heaven.  We fall more easily than we rise.  We fall easily; it requires great labor, a great deal of sweat to climb upwards...

Do not give up hope though the climb is arduous, and difficult, and engenders despair.  Do not lose confidence O man,: the Lord is up there on the fifteenth step.  He is watching over you; he is helping you...Mark what it [Scripture] does say: Jacob saw Him leaning over the ladder.  Just realise what that means: from where He was standing, He stooped down and lowered Himself that we might ascend.  The Lord stooped down; for your sake he humbled himself; climb up, therefore with safety and confidence.

He therefore instructs us to 'meditate upon the mystical significance of Jacob's ladder', for he argues, to climb from earth to heaven requires great pain, severe effort.

St Bede on St Benedict's ladder of humility

Finally, a few comments from St Bede, who takes us back to St Benedict's teaching on the psalms of ascent:

They arrive as far as the steps that come down from the city of David when one has learned to advance by means of spiritual desires from the common life of the faithful to the things of heaven.  For the steps that come down from the city of David to the lower parts of the city of Jerusalem are the aids of divine inspiration or protection by which we should ascend to his kingdom. For David made the steps by which we should ascend to his city when divine mercy taught us the order of the virtues by which we may seek heavenly things and when it granted us the gift of seeking these same virtues.  Doubtless it is about these steps that the psalmist said: Blessed is the man whose help is from you O Lord; he has placed ascents in his heart., and so on until he says: They will walk from virtue to virtue; the God of gods will be seen in Zion. (Ps 83:6-8).  

The builders of the holy city arrive at these steps, therefore, after building the walls of the Pool of Siloa and the King's Garden when, after the mysteries of the Lord's incarnation have been revealed whereby the Gentile world blind from birth  has been cleansed and illuminated, and after the sprouts of good action have begun to grow through faith, holy teachers at the appropriate moment more diligently reveal the progress of the virtues to their hearers, whereby they may ascend to the vision of their Creator, namely him 'of the strong hand' or 'the desirable one', which is the meaning of the name David.   

Benedict, a father very reverend both in his name and in his life, realized that these steps especially consist in humility when, interpreting our journey to celestial things to be designated by the ladder shown to the Patriarch Jacob, by which angels ascended and descended, he distinguished in a very careful and pious examination the steps of the ladder itself as the increments and stages of good works that are performed through humility...(On Ezra and Nehemiah, trans  deGregorio, pp171-2)

I hope you have found this series of use, and wish you a joyous Easter.  Please if you would, remember me in your prayers.

William Blake The three Marys at the tomb

A Good Friday meditation on the Gradual Psalms

Today, I want to provide some comments on these psalms from St Fulgentius of Ruspe, a contemporary of St Benedict, that seem to me particularly apposite for the day:

Just as one who returns to his homeland [Psalm 119] always has more of the trail ahead of him until he arrives, so we also, as long as we are in this mortal body, are away from the Lord.  For us in the present life is a road in which we always have room for being able to make progress, until, with God leading us, we are able to reach that eternal homeland of blessed immortality.

Therefore it is a great blessing in the present age to love in such a way that each member of the faithful applies himself to spiritual progress but not, however, at any time proudly attributing this to his own power.  Rather, with humble heart he asks God for a ceaseless guarding of the gift received [Ps 122], from whom emanates not just the beginning but also the perfecting of every good will....

There is no period in this life in which the enemy does not set a trap for people; no one can escape his snares with his own strength except that one whom God has deigned to free by his grace through Jesus Christ our Lord...So the prophet too proclaims that his feet will be freed from the snare not by his own power but by the divine gift..in another text, whom the Lord has deigned to transfer to safety and happiness for eternity, it is said:'Our soul has escaped like a bird from the snare of the fowlers; the snare has been broken are we have escaped'. [Ps 123] ...

Here we overcome the adversary if we fight with tears and prayers and continuing humility of heart.  It is written that 'The prayer of the humble pierces the clouds...and it will not desist until the Most High responds'.  Therefore the weeping of the humble contributes greatly to the destruction of carnal concupiscence.   The tears which come from compunction of heart both conquer the enemy and gain for us the gift of triumphal happiness.  For those 'who go out weeping, bearing the seed for sowing, shall come home with shouts of joy, carrying their sheaves' [Ps 125].  

How well does the holy prophet teach that the seeds of good works must be watered by a river of tears!  No seeds germinate unless they are watered; nor does fruit come forth from the seed if deprived of the aid of water.  Accordingly, we too, if we wish to keep the fruits of our seeds, let us not stop watering our seeds with tears which must be poured out more from the heart than from the body.  Therefore it is said to us through the prophet that we need to rend 'our hearts and not our clothing'; something we can do when we recall that we ourselves, even if not in deed, frequently sin in thought.  Because the 'earthly tent burdens the thoughtful mind' and our land does not cease to produce thorns and thistles for us.  We are unable to get to eating our bread, unless we will have been worn out by weariness and the sweat of our brow...

Therefore although we have reason to thank God, because by his free mercy, he has subjected us to himself so that we are humble, still we have reason to have to beseige the divine ears with continuous prayers; because as long as we are in this mortal body, just as we cannot be without sin, so we are not yet able to show forth perfect humility to the divine commands...(trans Robert B Eno, in Fulgentius Selected Works).

And you can find the final part in this series here. 

The Gradual Psalms and the Triduum

As we enter the last few days of Lent, and start the sacred Triduum, I thought I would end this series by providing a few sources to stimulate meditation that pull the whole set of psalms together in various ways.

To start with, here is Cassiodorus' summary of the fifteen steps represented by each psalm (I've inserted notes on which hour they are said at in the Benedictine Office):

Terce

On the first step he denotes loathing of the world, after which there is haste to attain zeal for all the virtues.

Secondly, the strength of divine protection is explained, and it is demonstrated that nothing can withstand it.

Thirdly, the great joy of dwelling with pure mind in the Lord's Church is stated.

Sext

Fourth, he teaches us that we must continually presume on the Lord's help whatever the constraints surrounding us, until He takes pity and hears us.

Fifth, he warns us that when we are freed from dangers, we must not attach any credit to ourselves, but attribute it all to the power of the Lord.

In the sixth, the trust of the most faithful Christian is compared to immovable mountains.

None

In the seventh, we are told how abundant is the harvest reaped by those who sow in tears.

In the eighth, it is said that nothing remains of what any individual has performed by his own will; only the things built by the sponsorship of the Lord are most firmly established.

In the ninth, it is proclaimed that we become blessed through fear of the Lord, and that all profitable things are granted us.

Monday Vespers

In the tenth, he inculcates in committed persons the patience which he commands through the words of the Church.

Tuesday Vespers

In the eleventh, as penitent he cries from the depths to the Lord, asking that the great power of the Godhead be experienced by the deliverance of mankind.

In the twelfth, the strength of meekness and humility is revealed.

In the thirteenth, the promise of the holy incarnation and the truth of the words spoken are demonstrated.

In the fourteenth, spiritual unity is proclaimed to the brethren, and to them the Lord's benediction and eternal life are shown to accrue.

Compline

In the fifteenth, there is awakened in the course of the Lord's praises that perfect charity than which nothing greater can be expressed, and nothing more splendid discovered. As the apostle attests: God is love.  So let us continually meditate on the hidden nature of this great miracle, so that by ever setting our gaze on such things, we may avoid the deadly errors of the world.

The number of these psalms contains this further mystery: when the five bodily senses, by which human frailty incurs all sin, are overcome by the power of the Trinity, this leads us to the fifteenth height of the psalms of the steps; thus the body's weakness is eliminated, and eternal rewards are bestowed on those who conquer it.

And for the next part in this series, continue on here.

Unity through Christ - Psalm 132 (Gradual Psalm no 14)

Psalm 132 is the fourteenth, or second last, of the gradual psalms (the last of the set concludes Compline each day in the Benedictine Office).  At three verses as it is arranged in most bibles, it is one of the three shortest in the psalter.

The psalm points us to the unity that can only come through Christ, and so it is perhaps significant that it it is the fourteenth psalm of the group, a number associated with the coming of Christ by virtue of the three groups of fourteen generations listed in Matthew 1.

Vulgate	Douay-Rheims
Canticum graduum David.	A gradual canticle of David.
Ecce quam bonum, et quam jucúndum * habitáre fratres in unum.	Behold how good and how pleasant it is for brethren to dwell together in unity:
2  Sicut unguéntum in cápite, * quod descéndit in barbam, barbam Aaron.	Like the precious ointment on the head, that ran down upon the beard, the beard of Aaron,
3  Quod descéndit in oram vestiménti ejus: * sicut ros Hermon, qui descéndit in montem Sion.	which ran down to the skirt of his garment: As the dew of Hermon, which descends upon mount Sion.
4  Quóniam illic mandávit Dóminus benedictiónem, * et vitam usque in sæculum	For there the Lord has commanded blessing, and life for evermore.

A psalm for monks?

The psalm is frequently seen by the Fathers, as particularly addressed to religious.  Cassiodorus, however, asserts its universal relevance:

"After the most holy preaching of the previous psalm, the prophet is now perched on the fourteenth step, and pro­claims to the people blessed unity, urging those who bind themselves to the Christian religion to persevere in the one accord of charity. 

Though some have opined that this message is to be addressed to monks, my view is that it is relevant to the harmony of Christians at large, for it is proclaimed not only to monasteries but to the whole Church, gathering into unity by a spiritual trumpet-blast all Christ's soldiers throughout the world. I do not dispute that it is addressed to saintly monasteries, but I believe that it should not be withdrawn from the general body. 

So the place which embraced the gathering of the faithful people was worthy of honour; clearly that assembly was estab­lished before the Lord's incarnation gained it from the Gentiles by His precious blood."

The opening  and closing lines make the psalm's subject matter clear, namely spiritual unity as a prerequisite for eternal life.  

The two images in between, however, of oil flowing down the beard of a priest, and dew on Mt Hermon, require a little more work to explicate, and are dealt with in the verse by verse notes that start in the this post.

Scriptural and liturgical uses of the psalm

NT references	Heb 13:1 (v1);
RB cursus	Tues Vespers+AN 2537
Monastic feasts etc	Gradual Psalms AN 2988 (1), 5261 (1, 3)
Roman pre 1911	Thurs Vespers
Responsories	6284 (St Caecilia) Common of Several martyrs/OSB All saints (6804, 7440)
Roman post 1911	1911-62: Thurs Vespers  . 1970:
Mass propers (EF)	PP23 GR (1-2)

And you can find the next part in this Lenten series here.

Arise O Lord - Psalm 131 (Gradual Psalm No 13)

Psalm 131 (132), the third psalm of Tuesday Vespers in the Benedictine Office, is longest of the gradual psalms, and the climax of the group.

At a literal level it has its historical origins in the dedication of the First Temple. The first half of the psalm is from the people/King’s perspective; the second half is God’s response.

Read Christologically, however, it can be read as prefiguring the Resurrection: now the appointed time has come for Christ to arise and enter the holy of holies to intercede for us.

Psalm 131 (132) – Memento Domine

Vulgate	Douay-Rheims
Canticum graduum.	A gradual canticle.
1 Meménto, Dómine, David, * et omnis mansuetúdinis ejus :	O Lord remember David, and all his meekness.
2  Sicut jurávit Dómino, * votum vovit Deo Jacob	2 How he swore to the Lord, he vowed a vow to the God of Jacob:
3  Si introíero in tabernáculum domus meæ, * si ascéndero in lectum strati mei :	3 If I shall enter into the tabernacle of my house: if I shall go up into the bed wherein I lie:
4  Si dédero somnum óculis meis, * et pálpebris meis dormitatiónem :	4 If I shall give sleep to my eyes, or slumber to my eyelids,
5  Et réquiem tempóribus meis : donec invéniam locum Dómino, * tabernáculum Deo Jacob.	5 or rest to my temples: until I find out a place for the Lord, a tabernacle for the God of Jacob.
6. Ecce audívimus eam in Ephrata: * invénimus eam in campis silvæ.	6 Behold we have heard of it in Ephrata: we have found it in the fields of the wood.
7  Introíbimus in tabernáculum ejus: * adorábimus in loco, ubi stetérunt pedes ejus.	7 We will go into his tabernacle: we will adore in the place where his feet stood. .
8  Surge, Dómine, in réquiem tuam, * tu et arca sanctificatiónis tuæ.	8 Arise, O Lord, into your resting place: you and the ark, which you have sanctified
9  Sacerdótes tui induántur justítiam: * et sancti tui exsúltent.	9 Let your priests be clothed with justice: and let your saints rejoice.
10  Propter David, servum tuum: * non avértas fáciem Christi tui.	10 For your servant David's sake, turn not away the face of your anointed.
11  Jurávit Dóminus David veritátem, et non frustrábitur eam: * de fructu ventris tui ponam super sedem tuam.	11 The Lord has sworn truth to David, and he will not make it void: of the fruit of your womb I will set upon your throne
12  Si custodíerint fílii tui testaméntum meum: * et testimónia mea hæc, quæ docébo eos.	12 If your children will keep my covenant, and these my testimonies which I shall teach them:
13  Et fílii eórum usque in sæculum: * sedébunt super sedem tuam.	Their children also for evermore shall sit upon your throne.
14  Quóniam elégit Dóminus Sion: * elégit eam in habitatiónem sibi.	13 For the Lord has chosen Sion: he has chosen it for his dwelling.
15  Hæc réquies mea in sæculum sæculi: * hic habitábo, quóniam elégi eam.	14 This is my rest for ever and ever: here will I dwell, for I have chosen it.
16  Víduam ejus benedícens benedícam: * páuperes ejus saturábo pánibus.	15 Blessing I will bless her widow: I will satisfy   her poor with bread.
17  Sacerdótes ejus índuam salutári: * et sancti ejus exsultatióne exsultábunt.	16 I will clothe her priests with salvation, and her saints shall rejoice with exceeding great joy.
18  Illuc prodúcam cornu David: * parávi lucérnam Christo meo.	17 There will I bring forth a horn to David: I have prepared a lamp for my anointed
19  Inimícos ejus índuam confusióne: * super ipsum autem efflorébit sanctificátio mea.	18 His enemies I will clothe with confusion: but upon him shall my sanctification flourish.

Historical context

Psalm 131 was probably originally composed for the occasion of King David’s bringing the Arc of the Covenant to Mount Sion.

The psalm is put in the mouths of two different speakers: Solomon, recalling the oath his father swore, and then commenting on the ceremony of the dedication of the Temple (vs 5-10); and finally God himself.

Two separate sections of Scripture provide some context for the psalm.

First, 2 Chronicles chapters 6 to 7, quotes at length from it, and provides an extended description of the ceremonies that accompanied the dedication of the Temple.  Its text provides something of a commentary on the psalm, so do go and read it in full.

In particular, it recounts a speech of Solomon on the occasion, which starts with how God chose the people of Israel as his own, brought them out of slavery, and promised to dwell with them in a cloud; how he chose the city of Jerusalem, David as its King, and recounts David’s plans to build the Temple.  It also notes that while David wanted to build the Temple himself, God instructed him to leave the task to his son, Solomon.  The chapter also contains an extended discussion of the covenant, and behaviour required of the Israelites, as well as of the rationale for having a Temple with God’s Real Presence.

Secondly, chapter 7 of 2 Samuel also records the story of David’s commitment to building God a Temple, and God’s promises in return, this time in the form of a vision to the prophet Nathan.  Here is an extract from that chapter:

“Now when the king dwelt in his house, and the LORD had given him rest from all his enemies round about, the king said to Nathan the prophet, "See now, I dwell in a house of cedar, but the ark of God dwells in a tent." And Nathan said to the king, "Go, do all that is in your heart; for the LORD is with you." But that same night the word of the LORD came to Nathan, "Go and tell my servant David, `Thus says the LORD: Would you build me a house to dwell in? I have not dwelt in a house since the day I brought up the people of Israel from Egypt to this day, but I have been moving about in a tent for my dwelling. In all places where I have moved with all the people of Israel, did I speak a word with any of the judges of Israel, whom I commanded to shepherd my people Israel, saying, "Why have you not built me a house of cedar?"' Now therefore thus you shall say to my servant David, `Thus says the LORD of hosts, I took you from the pasture, from following the sheep, that you should be prince over my people Israel; and I have been with you wherever you went, and have cut off all your enemies from before you; and I will make for you a great name, like the name of the great ones of the earth… Moreover the LORD declares to you that the LORD will make you a house. When your days are fulfilled and you lie down with your fathers, I will raise up your offspring after you, who shall come forth from your body, and I will establish his kingdom. He shall build a house for my name, and I will establish the throne of his kingdom for ever. I will be his father, and he shall be my son….And your house and your kingdom shall be made sure for ever before me; your throne shall be established for ever.'"

The final part of Psalm 131 records God’s promises to David.  And the promises are these: that his descendants will rule forever, a promise realized in the kingship of Christ (vs 11-12); that God will dwell with them, as he does in the Church and in heaven (vs 13-14); that the people will be blessed abundantly with spiritual food through the sacraments, Sacred Scripture and grace (vs 15-16); that he will send the Messiah, after first preparing the way for him through St John the Baptist (vs 18); his enemies will be defeated and brought to shame at the end (vs 19).

Septuagint vs the Hebrew Masoretic Text

Some of the early Church Fathers such as Tertullian claimed that the Jews were changing Scripture in reaction to Christian interpretations of it.  It was a claim discounted by many, including, most vociferously, St Jerome, but recent evidence from the Dead Sea Scrolls provides some support for the claim.  And this psalm provides some possible examples, with competing interpretations of the underlying Hebrew, and clearly differing text traditions contained in the Septuagint Greek compared to the much later Jewish Masoretic Text tradition.

In verse one for example, in the Septuagint/Vulgate the speaker lauds King David’s meekness.  The Masoretic Text reads the same text as ‘labours’ or ‘devotedness’.  Both interpretations of the text are theoretically possible (due to early Hebrew’s lack of vowel indications) - but it may also be that those early Jews reacting to Christian claims preferred not to highlight Christ-like meekness!  In later verses the MT omits some text found in the Septuagint, and is differs significantly in others.

Liturgical and Scriptural uses of the psalm

NT references	Acts 7:46 (v5); Acts 2:30, Lk 1:32-39 (v11); Lk1:69 (v19)
RB cursus	Tues Vespers
Monastic feasts etc	Christmas octave vespers (alternating days); Second Vespers of a Confessor Bishop AN 2713 (1); 1368 (6-10)
Roman pre 1911	Thursday Vespers
Responsories	6921(4); Easter 4&5 v6-7 – 6069; 2106 (11); 3012 (14); 4218 (17-8)
Roman post 1911	1911-62: Wed Vespers . 1970: Evening Prayer - Thursday of Week Three
Mass propers (EF)	Common of a confessor, St Paulinus - Statuit, Sacerdotes IN V(1)

For the first set of notes on the individual verses of this psalm, continue here.

Alternatively, to go to the next part in this Lenten series, go here.

The twelve degrees of humility - Psalm 130 (Gradual Psalm No 12)

Psalm 130, the twelfth of the series (and the number is significant, not least because since St Benedict then sets out twelve degrees of humility), is a particularly important psalm from the perspective of Benedictine spirituality, because St Benedict cites it as one of the foundations for his discussion of the virtue of humility.  It is also the second psalm of Tuesday Vespers in the Benedictine Office..

Psalm 130 (131)

Vulgate	Douay-Rheims
Canticum graduum David.	A gradual canticle of David.
1 Dómine, non est exaltátum cor meum: * neque eláti sunt óculi mei.	1 Lord, my heart is not exalted: nor are my eyes lofty
2  Neque ambulávi in magnis: neque in mirabílibus super me.	Neither have I walked in great matters, nor in wonderful things above me.
3  Si non humíliter sentiébam: * sed exaltávi ánimam meam.	2 If I was not humbly minded, but exalted my soul:
4  Sicut ablactátus est super matre sua: * ita retribútio in ánima mea.	As a child that is weaned is towards his mother, so reward in my soul
5  Speret Israël in Dómino: * ex hoc nunc et usque in sæculum.	3 Let Israel hope in the Lord, from henceforth now and for ever.

Scriptural and historical context

Psalm 130 is one of the shortest in the psalter at three verses.

St Alphonsus Liguori suggests that it is a response by David to accusations of pride from Saul and his followers, saying:

"David complains that Saul and his followers accuse him of being proud, and calls God to witness against this calumny."

Reading the psalm Christologically, we can see it as a portrait of Jesus' perfect humility, in his willingness to take human form and become a baby, totally dependent on his mother, humble himself and become obedient even unto death.  In this group of psalms that we have now reached, his humility is vindicated by his descent into hades to free the holy souls, and coming Resurrection.

Humility and meekness

As noted above, St Benedict uses this psalm in his discussion of the virtue of humility in Chapter 7 of his Rule:

Holy Scripture, brethren, cries out to us, saying, "Everyone who exalts himself shall be humbled, and he who humbles himself shall be exalted" (Luke 14:11). In saying this it shows us that all exaltation is a kind of pride, against which the Prophet proves himself to be on guard when he says, "Lord, my heart is not exalted, nor are mine eyes lifted up; neither have I walked in great matters, nor in wonders above me" But how has he acted? "Rather have I been of humble mind than exalting myself; as a weaned child on its mother's breast, so You solace my soul".

Unsurprisingly then, many writers have seen this psalm as above exemplifying monastic life.  Fr Pius Pasch's commentary on the Divine Office for example includes this comment:

"In this singing of this beautiful hymn with its unmistakably mystic character, picture some little convent in which consecrated souls serve our Lord humbly and joyfully. Be thankful for the blessings of religious communities, and beg for more vocations."

Growth in the spiritual life

The psalm provides us with three images of humility.

The first is of a person who practices custody of the eyes, keeping his head bowed and eyes downcast pondering his sins and coming judgment (RB 7).  It is probably not accidental that St Benedict's twelfth degree of humility reflects the opening verse of the twelfth of the Gradual psalms!

The second image is of a person who does not 'walk' in things above him, that is, engage in pride arising from our words and actions.  Instead, the humble person recognises that, as St Benedict urges in his sixth and seventh degrees of humility, we regard ourselves as bad and unworthy workmen, of lower and of less account than all others.

The final image is of a child being weaned from its mother's breast.  Pope Benedict XVI comments on this:

"We have listened to only a few words, about 30 in the original Hebrew, of Psalm 131[130]. Yet they are intense words that convey a topic dear to all religious literature: spiritual childhood. Our thoughts turn spontaneously to St Thérèse of Lisieux, to her "Little Way", her "remaining little" in order to be held in Jesus' arms (cf. Story of a Soul, Manuscript "C", p. 208). Indeed, the clear-cut image of a mother and child in the middle of the Psalm is a sign of God's tender and maternal love, as the Prophet Hosea formerly expressed it: "When Israel was a child I loved him.... I drew [him] with human cords, with bands of love; I fostered [him] like one who raises an infant to his cheeks... I stooped to feed my child" (Hos 11: 1, 4). "

For notes on the individual verses of this psalm, continue on to here.

Or to continue to the next part in this Lenten series, go here.

With Christ there is plenteous redemption: Psalm 129 (Gradual Psalm No 11)

As well as being one of the Gradual Psalms, Psalm 129 is also the first psalm of Tuesday Vespers, one of the seven penitential psalms; and is used in the Office of the Dead at Vespers.  It is a traditional preparatory prayer for Mass; and it carries an indulgence if said for those in purgatory.

Psalm 129: De Profundis

Vulgate	Douay-Rheims
Canticum graduum.	Canticum graduum.
De profúndis clamávi ad te, Dómine: * Dómine, exáudi vocem meam :	Out of the depths I have cried to you, O Lord:
2  Fiant aures tuæ intendéntes: * in vocem deprecatiónis meæ.	2 Lord, hear my voice. Let your ears be attentive to the voice of my supplication.
3  Si iniquitátes observáveris, Dómine: * Dómine, quis sustinébit?	3 If you, O Lord, will mark iniquities: Lord, who shall stand it.
4  Quia apud te propitiátio est: * et propter legem tuam sustínui te, Dómine.	4 For with you there is merciful forgiveness: and by reason of your law, I have waited for you, O Lord.
5  Sustinuit ánima mea in verbo ejus: * sperávit ánima mea in Dómino.	My soul has relied on his word: 5 My soul has hoped in the Lord.
6  A custódia matutína usque ad noctem: * speret Israël in Dómino.	6 From the morning watch even until night, let Israel hope in the Lord.
7  Quia apud Dóminum misericórdia: * et copiósa apud eum redémptio.	7 Because with the Lord there is mercy: and with him plentiful redemption.
8  Et ipse rédimet Israël: * ex ómnibus iniquitátibus ejus.	8 And he shall redeem Israel from all his iniquities

Historical context

The psalm is almost certainly Davidic in origin, as 2 Chronicles 6:36-42, which is part of a prayer of King Solomon, alludes to and explains this psalm, and explicitly mentions Solomon's father, King David in this context.

Here are the verses in question from Chronicles:

"And if they sin against you (for there is no man that sins not) and you be angry with them, and deliver them up to their enemies, and they lead them away captive to a land either afar off, or near at hand, and if they be converted in their heart in the land to which they were led captive, and do penance, and pray to you in the land of their captivity saying: We have sinned, we have done wickedly, we have dealt unjustly: And return to you with all their heart, and with all their soul, in the land of their captivity, to which they were led away, and adore you towards the way of their own land which you gave their fathers, and of the city, which you have chosen, and the house which I have built to your name: Then hear from heaven, that is, from your firm dwelling place, their prayers, and do judgment, and forgive your people, although they have sinned: For you are my God: let your eyes, I beseech you, be open, and let your ears be attentive to the prayer, that is made in this place. Now therefore arise, O Lord God, into your resting place, you and the ark of your strength: let your priests, O Lord God, put on salvation, and your saints rejoice in good things. O Lord God, turn not away the face of your anointed: remember the mercies of David your servant."

Christ reconciles us, reopening the way to heaven

The focus of this psalm is Christ's work of reconciliation: we have now surely reached the harrowing of hell and reopening of the way to heaven in Christ's life recounted in the psalms of the steps.

In this light, Pope Benedict XVI suggested that:

"the text is first and foremost a hymn to divine mercy and to the reconciliation between the sinner and the Lord, a God who is just but always prepared to show himself "a merciful and gracious God, slow to anger and rich in kindness and fidelity, continuing his kindness for a thousand generations, and forgiving wickedness and crime and sin" (Ex 34: 6-7)."

In terms of our own ascent in imitation of him, one can perhaps use it to meditate on incidents in the Gospel such as Jesus' repeated forgiveness of sins of those he healed through his miracles; the tearful repentance of Mary Magdalene; the story of the woman caught in adultery and more.

Competing textual traditions?

It is worth noting that this is one of those psalms where the Septuagint Greek (and thus Vulgate) and the (late medieval) Hebrew Masoretic Text are in places very different, in ways impossible to reconcile by looking for alternative readings of the Hebrew.  

In particular, from verse 4 onwards, the Hebrew puts much more emphasis on fear of God, and omits two references to the hope of the Christ’s redemption.  This may well be the result of early rabbinical reaction to Christianity, and in fact the text is so corrupt that in places even protestant bibles that usually prefer the Hebrew have adopted the Vulgate tradition.

Liturgical and Scriptural uses of the psalm

NT references	Rom 3:24 (v7); Mt 1:21, Tit 2:14, Rev 1:5 (v8)
RB cursus	Tuesday Vespers+AN 2116 (1-2); 4990 (4)
Monastic feasts etc	Gradual Psalms Penitential Psalms Vespers of Christmas and its octave (alternating days); 1 Vespers of Sacred Heart; Office of the Dead V AN 5094(4-5), 1446 (7)
Roman pre 1911	Wednesday Vespers
Responsories	Epiphanytide Sat v2 (6495); 7143 (alt verse for Sept 3&4)
Roman post 1911	1911-62: Wednesday Vespers
Mass propers (EF)	Septuagesima Sunday: TR (1-4) PP22 IN 1-4 PP 23: AL (102); OF (1-2)

You can find notes on the individual verses of the psalm in this series, in the context of Vespers:

Introduction to Psalm 129
Ps 129 v 1-2
Ps 129 v3-5a
Ps 129 v5b-6
Ps 129 v7-8