Psalm 128 verse 3

Rubens

Verse 3 of Psalm 128 speaks of the persecution the just often suffer.

Psalm 128: Saepe expugnaverunt 

Vulgate	Douay-Rheims
Canticum graduum.	A gradual canticle.
1 Sæpe expugnavérunt me a juventúte mea, * dicat nunc Israël:	Often have they fought against me from my youth, let Israel now say.
2  Sæpe expugnavérunt me a juventúte mea: * étenim non potuérunt mihi.	2 Often have they fought against me from my youth: but they could not prevail over me.
3  Supra dorsum meum fabricavérunt peccatóres: * prolongavérunt iniquitátem suam.	3 The wicked have wrought upon my back: they have lengthened their iniquity.
4  Dóminus justus concídit cervíces peccatórum: * confundántur et convertántur retrórsum omnes, qui odérunt Sion.	4 The Lord who is just will cut the necks of sinners: 5 Let them all be confounded and turned back that hate Sion.
5  Fiant sicut fœnum tectórum: * quod priúsquam evellátur exáruit:	6 Let them be as grass upon the tops of houses: which withers before it be plucked up:
6  De quo non implévit manum suam qui metit: * et sinum suum qui manípulos cólligit.	7 Who with the mower fills not his hand: nor he that gathers sheaves his bosom.
7  Et non dixérunt qui præteríbant: Benedíctio Dómini super vos: * benedíximus vobis in nómine Dómini.	8 And they that passed by have not said: The blessing of the Lord be upon you: we have blessed you in the name of the Lord.

Notes on the verse

3. Supra dorsum meum fabricaverunt peccatores; prolongaverunt iniquitatem suam.

The wicked have wrought upon my back: they have lengthened their iniquity (DR).

Supra (upon) dorsum (the back) meum (my) fabricavérunt (they have fashioned/made/devised/wrought) peccatóres (the sinners/the wicked) 

Ladouceur (The Latin Psalter Introduction, Selected Text and Commentary) notes that this phrase can be literally translated as ‘upon my back, sinner were framing (ie devising) schemes; the Hebrew Masoretic Text here uses the metaphor of  ‘ploughers ploughing upon my back’ (ie whipping), and the Monastic Diurnal and Knox translations follows this: 'I bent my back to the oppressor, and long was the furrow ere the plough turned' (Knox).  The Hebrew word is, however, ambiguous, and can also mean devising (in a bad sense), so the (more ancient) Greek (and Vulgate reflecting this) should probably be preferred.

supra, prep, with abl., and adv.  on, upon
dorsum, i, n.t the back.
fabrico(r), avi, atum, are to make, fashion, build; to forge anything out of hard material.

prolongavérunt (they have prolonged) iniquitátem (the sin/wickedness/iniquity) suam (his/her/its)

Note that suam here refers to iniquitatem, so in English is plural, so translated as their.

peccator, oris, m.  a sinner, transgressor; the wicked, the godless.
prolongo, avi, atum, are  to prolong, lengthen, draw out.
iniquitas, atis, f (iniquus), iniquity, injustice, sin. 

How do we resist the assaults of those who would attack us? St Benedict's tools of good works (RB 4) offer several defenses against such assaults:

To fear the Day of Judgement.

To dread hell.

To desire eternal life with all spiritual longing.

To keep death daily before one's eyes.

To keep constant guard over the actions of one's life.

To know for certain that God sees one everywhere.

When evil thoughts come into one's heart, to dash them at once on the rock of Christ and to manifest them to one's spiritual father.

And you can find on the next verses here.