Psalm 89 explicitly tells us that Yahweh entered into a covenant with David (v. 28), which makes David the firstborn over the kings of the earth (v. 27) and promises a perpetual seed and sonship (vv. 26, 29).

The Psalm as a whole, however, is about an apparently broken covenant. No sooner has the Psalmist repeated Yahweh’s promise to preserve David’s seed as the sun and moon (vv. 36-37) than the Psalmist suddenly protests that Yahweh has in fact cast off HIs anointed, broken covenant, and cast his crown to the ground (vv. 38-39). And the protest doesn’t let up through the rest of the Psalm. The only hope is that Yahweh will remember (vv. 47, 50), but the Psalm ends with enemies still mocking Yahweh’s anointed (v. 51).

The Psalm places David on the cross, and doesn’t let him off. In that respect, the Psalm is a summary of the history of the Davidic house: Yahweh promises a perpetual seed, but the promise doesn’t appear to hold. So Israel waits for Yahweh to remember and raise up the seed of David, the one who calls Yahweh Father, the firstborn of the kings of the earth.