These videos contain Palestrina's settings of the Lamentations of Jeremiah, passages which are read or sung during the Holy Week Office of Tenebrae. You can follow along with the office at Divinum Officium; enter (for instance) 4-17-2014 in the date field, then click Matutinum (i.e., Matins).
Tenebrae actually begins on Wednesday of Holy Week (i.e., the eve of the day to which it actually belongs); today it's celebrated in the early evening, but historically Matins and Lauds were middle-of-the-night services in the monastery. From the Catholic Encyclopedia, via New Advent:
Tenebræ is the name given to the service of Matins and Lauds belonging to the last three days of Holy Week. This service, as the "Cæremoniale episcoporum" expressly directs, is to be anticipated and it should be sung shortly after Compline "about the twenty-first hour", i.e. about three p.m. on the eve of the day to which it belongs. .... Originally Matins on these days, like Matins at all other seasons of the year, were sung shortly after midnight, and consequently if the lights were extinguished the darkness was complete. That this putting out of lights dates from the fifth century, so far at least as regards the night Office, is highly probable. Both in the first Ordo Romanus and in the Ordo of St. Amand published by Duchesne a great point is made of the gradual extinction of the lights during the Friday Matins; though it would seem that in this earliest period the Matins and Lauds of the Thursday were sung throughout with the church brightly illuminated (ecclesia omni lumine decoretur). On Friday the candles and lamps were gradually extinguished during the three Nocturns, while on Saturday the church was in darkness from beginning to end, save that a single candle was kept near the lectern to read by.
There are 10 YouTube videos of the Palestrina music; they are coded so that one follows the last. They're very beautiful. Some of the videos contain Gregorian responsories not part of the book of Lamentations. The words of Lamentations itself in Latin and English are here, at Choral Public Domain Library.
Here's just Chapter 1 in English:
1:1 ALEPH. How lonely sits the city that was full of people! How like a widow has she become, she that was great among the nations! She that was a princess among the cities has become a vassal.
1:2 BETH. She weeps bitterly in the night, tears on her cheeks; among all her lovers she has none to comfort her; all her friends have dealt treacherously with her, they have become her enemies.
1:3 GHIMEL. Judah has gone into exile because of affliction and hard servitude; she dwells now among the nations, but finds no resting place; her pursuers have all overtaken her in the midst of her distress.
1:4 DALETH. The roads to Zion mourn, for none come to the appointed feasts; all her gates are desolate, her priests groan; her maidens have been dragged away, and she herself suffers bitterly.
1:5 HE. Her foes have become the head, her enemies prosper, because the LORD has made her suffer for the multitude of her transgressions; her children have gone away, captives before the foe.
1:6 VAU. From the daughter of Zion has departed all her majesty. Her princes have become like harts that find no pasture; they fled without strength before the pursuer.
1:7 ZAIN. Jerusalem remembers in the days of her affliction and bitterness all the precious things that were hers from days of old. When her people fell into the hand of the foe, and there was none to help her, the foe gloated over her, mocking at her downfall.
1:8 HETH. Jerusalem sinned grievously, therefore she became filthy; all who honored her despise her, for they have seen her nakedness; yea, she herself groans, and turns her face away.
1:9 Her uncleanness was in her skirts; she took no thought of her doom; therefore her fall is terrible, she has no comforter. "O LORD, behold my affliction, for the enemy has triumphed!"
1:10 IOD. The enemy has stretched out his hands over all her precious things; yea, she has seen the nations invade her sanctuary, those whom thou didst forbid to enter thy congregation.
1:11 CAPH. All her people groan as they search for bread; they trade their treasures for food to revive their strength. "Look, O LORD, and behold, for I am despised."
1:12 LAMED. "Is it nothing to you, all you who pass by? Look and see if there is any sorrow like my sorrow which was brought upon me, which the LORD inflicted on the day of his fierce anger."
1:13 MEM. "From on high he sent fire; into my bones he made it descend; he spread a net for my feet; he turned me back; he has left me stunned, faint all the day long.
The capitalized words are Hebrew letters; Lamentations is another Old Testament acrostic. Here's CPDL on Lamentations.
Lamentationes Ieremiae (English Lamentations of Jeremiah)
In the Greek and Latin Bibles there are five songs of lament bearing the name of Jeremiah, which follow the Book of the Prophecy of Jeremias. In the Hebrew these are entitled Kinôth. from their elegiac character, or the 'Ekhah songs after the first word of the first, second, and fourth elegies; in Greek they are called Threnoi, in Latin they are known as Lamentationes. The superscription to Lamentations in the Septuagint and other versions throws light on the historical occasion of their production and on the author: "And it came to pass, after Israel was carried into captivity, and Jerusalem was desolate, that Jeremiah the prophet sat weeping, and mourned with this lamentation over Jerusalem, and with a sorrowful mind, sighing and moaning, he said:".
To a man like Jeremiah, the day on which Jerusalem became a heap of ruins was not only a day of national misfortune, for, in a religious sense, Jerusalem had a peculiar importance in the history of salvation, as the footstool of Jahweh and as the scene of the revelation of God and of the Messias. Consequently, the grief of Jeremiah was personal, not merely a sympathetic emotion over the sorrow of others, for he had sought to prevent the disaster by his labours as a prophet in the streets of the city. All the fibres of his heart were bound up with Jerusalem; he was now himself crushed and desolate.
In all five elegies the construction of the verses follows an alphabetical arrangement. The first, second, fourth, and fifth laments are each composed of twenty-two verses, to correspond with the number of letters in the Hebrew alphabet; the third lament is made up of three times twenty-two verses. In the first, second, and fourth elegies each verse begins with a letter of the Hebrew alphabet, the letters following in order, as the first verse begins with ALEPH, the second with BETH etc.
The Lamentations have received a peculiar distinction in the Liturgy of the Church in the Office of Passion Week. If Christ Himself designated His death as the destruction of a temple, "he spoke of the temple of his body" (John 2:19-21), then the Church surely has a right to pour out her grief over His death in those Lamentations which were sung over the ruins of the temple destroyed by the sins of the nation.
You can also download a PDF of the Office of Tenebrae for Good Friday - in English - from the (Catholic) Archdiocese of St. Louis' Institute of Sacred Music (where there are many other fine resources generously offered for free).
Here's Rembrandt's "Jeremiah Lamenting the Destruction of Jerusalem":