What does Psalms Chapter 88 say, and which statements belong to its speaker?

Misericordias Domini is the incipit. The heading interprets the church's promised perpetuity despite afflictions; understanding is for Ethan the Ezrahite. The speaker will sing mercies and make truth known through generations. He recalls God's words about mercy built forever, truth in heavens and a covenant with the elect and oath to David, whose seed and throne God will settle through generations.

The heavens shall confess wonders and truth in saints' assembly. Questions compare none in clouds or sons of God to the Lord, terrible in saints' assembly. He rules the sea and appeases waves, humbled the proud one and scattered enemies. Heaven, earth, world and fullness are His; He created north and sea. Thabor and Hermon shall rejoice. The speaker asks His strong arm, hand strengthened and right hand exalted. Justice and judgment prepare the throne and mercy and truth shall go before His face. Those knowing jubilation are blessed and shall walk in the face's light, rejoice and be exalted; the horn is exalted in favor and protection belongs to the Lord and king to Israel's Holy One.

God's vision words recall help set on a mighty chosen man, David found and anointed with holy oil. His hand and arm shall help and strengthen David, foes shall not prevail, haters shall be cut down, and mercy and truth accompany him. His hand shall be on sea and right hand on rivers. He shall call God father, God and support of salvation, and be made firstborn above earth's kings. Mercy and covenant remain faithful and seed and throne shall last as heaven's days. If children forsake law, profane justices and break commands, transgression receives rod and stripes, yet mercy, truth, covenant and spoken words will not be voided. God swore by holiness not to lie to David; seed forever and throne like sun and perfect moon with faithful heavenly witness follow.

The lament then says God rejected and despised His anointed, overthrew the servant's covenant and profaned sanctuary. The separate note says this seems to concern Babylonian captivity, when promises seemed set aside for a while because of sins; uncertainty remains. Hedges broke, strength was fear, passers robbed, neighbors reproached, adversaries' right hand rose and enemies rejoiced. Sword help was turned away and battle help withheld, purification ceased, throne fell to ground, days were shortened and confusion covered him. The text does not say Rahab, north and south, rock of salvation or shortened youth here.

The speaker asks how long anger burns and asks remembrance of his substance, whether all humans were made in vain and who lives without death or delivers his soul from hell. He asks where ancient mercies sworn to David are, and remembrance of servants' reproach held in his bosom from many nations and enemies' reproach against the change of the anointed. Footsteps is not substituted for change. The chapter closes blessing the Lord forever with So be it twice, without an invented completed restoration.