R. Parce Domine, parce populo tuo: ne in aeternum irascaris nobis.
(Spare, O Lord, spare Your people: lest You be angry with us forever.)
1. Flectamus iram vindicem, ploremus ante Judicem; clamemus ore supplici, dicamus omnes cernui.
(Let us bow before the avenging wrath, let us weep before the Judge; let us cry out with words of supplication, let us all speak, falling prostrate.)
2. Nostris malis offendimus tuam Deus clementiam; effunde nobis desuper remissor indulgentiam.
(O God, by our wickedness we have offended Your clemency; pour forth on us from above, O forgiving One, Your pardon.)
3. Dans tempus acceptabile, da lacrimarum rivulis lavare cordis victimam, quam laeta adurat caritas.
(Giving us an acceptable time, grant to purify, in the rivers of our tears, the sacrifice of our hearts, enkindled by joyful charity.)
4. Audi, benigne Conditor, nostras preces cum fletibus in hoc sacro jejunio fusas quadragenario.
(Hear, O benign Creator, our prayers, with lamentations, poured forth during this holy fast of forty days.)
5. Scrutator alme cordium, infirma tu scis virium; ad te reversis exhibe remissionis gratiam.
(O beloved searcher of hearts, You know the weakness of mortal bodies; show to those returning to You the grace of forgiveness.)
English translations are essentially my own. Verse 3 was a tough one.
The antiphon is based on Joel 2:17.
Verse 1 is from Ex more docti mystico (Pope St. Gregory I), verse 5 (according to the revision by Pope Urban VIII). Verse 2 is from Ex more docti mystico, verse 6 (original).
Verse 3 is from O Sol salutis initimis (Pope Urban VIII), verse 2 (revision of Iam, Christe, sol iustitiae).
Verses 4 and 5 are from Audi, benigne Conditor (Pope St. Gregory I), verses 1 and 2.