English Basic Explanation - Chapter 89
The first verse of this Psalm identifies its author as Etan Ha'ezrahi, who is listed in the Book of Melachim I (5:11) as one of the wise men that lived in the time of King Shelomo (along with Heman Ha'ezrahi mentioned in the beginning of Psalm 88). Etan, like Heman, is identified in Divre Hayamim I (2:6) as a member of the tribe of Yehuda.
Others, however, as Rashi notes, identify Etan Ha'ezrahi here in Tehillim as a reference to Avraham Avinu, and it is thus he who composed this prayer.
This chapter is essentially a lamentation over the fall of "Malchut Bet David," the Davidic royal dynasty. It recalls and speaks at length of God's promise to David that his throne shall endure for eternity and achieve widespread fame and success (verses 4-5, 20-38), emphasizing the guarantee that even if his descendants sin and must be punished, they will not forfeit the right to the monarchy (verses 31-38). Yet, as the author laments, God has rejected the dynasty, allowing its fortresses to collapse and subjecting the kingdom to ridicule and scorn. The author wonders how much longer God's anger will endure (verse 47), and goes so far as to question the value of life and the world in the absence of "Malchut Bet David" (verse 48). He concludes by beseeching God not to disregard the enemies' blasphemous contempt for Him and for the Mashiah whose arrival we still await (verses 51-52).
Ibn Ezra, in his commentary to this Psalm (verse 1), writes that there was a certain Jewish scholar in Spain who refused to recite this chapter of Tehillim because it appears to accuse the Almighty of violating his oath to David. Indeed, the author speaks in harsh terms of God's rejection of the covenant He made with David (verses 39-40). Ibn Ezra, however, explains that these condemnations are the words of the enemies who destroyed the kingdom, not of the author himself. The author merely cites the enemies' blasphemous claims that God has broken His promise, in order to emphasize the "Hillul Hashem" (desecration of God's Name) that this tragedy has caused. Other commentaries, however, explain that these are, in fact, the author's own words, but that the author in no way denies or challenges God's justice. He readily acknowledges that the downfall of the Davidic dynasty was the result of the nation's disobedience, but is nevertheless bewildered over the long duration of exile. As the Radak (verse 39) explains, the seemingly endless exile makes it appear as though "Malchut Bet David" will never be restored, thus leaving the impression that God has violated His promise to David, Heaven forbid.
In truth, however, the author has never lost hope in the eventual return of the kingship. He concludes this chapter by exclaiming, "Blessed is God forever," which the Radak explains as a response to the Psalmist's prophetic vision of the Messianic era. Thus, while it might appear as though our nation's loss of kingship has become a permanent condition, we are guaranteed of its ultimate restoration and the return of the glorious period of David's monarchy.