so that my hand shall be established with him; my arm also shall strengthen him.
The writer of this psalm approaches God's throne with the covenant made to David as his anchor: God promised to sustain His favor toward this people forever through their king. He rehearses God's power in all creation and His faithfulness in redemption, yet the complaint that follows cuts sharp, God has seemingly abandoned His Church to her enemies, withdrawn all help and comfort, as though He had forgotten His own word.
AI summary
Commenting on Psalm 89:1-52
With whom my hand shall be established, or, "with whom my hand shall ever be present." The almightiness of God abides permanently with Jesus in his work as Redeemer and Ruler of his people. Mine arm also shall strengthen him. The fulness of divine power shall attend him.
The covenant God made with David and his seed was mentioned before (Psa 89:3, Psa 89:4); but in these verses it is enlarged upon, and pleaded with God, for favour to the royal family, now almost sunk and ruined; yet certainly it looks at Christ, and has its accomplishment in him much more than in David; nay, some passages here are scarcely applicable at all...
Commenting on Psalm 89:19-37