I have made a covenant with my chosen, I have sworn unto David my servant,
I have made a covenant with my chosen, I have sworn unto David, my servant, Thy seed will I establish for ever. The ground of my confidence that thy mercy and faithfulness shall be for ever to David's seed and people is thy covenant and oath of promise to him in 2 Samuel 7:10; 2 Samuel 7:12-16; 2 Samuel 7:19; 2 Samuel 7:24-25; 2 Samuel 7:29, Thou didst say (supply) I have made a covenant with my chosen." This covenant of God with David is the central axis round which this psalm revolves (see notes, Psalms 18:28-47). In Psalms 89:19-37 the Psalmist sets forth more fully this promise.
And build up thy throne to all generations. Inseparably dependent on this promise is the promise (Psalms 89:2). "Mercy shall be built up forever" (cf. also 2 Samuel 7:13). The literal building of the house of God, in purpose by David, in fact by David's son, Solomon, was closely connected with God's figurative building up of David's house and throne forever.