I will sing of the mercies of the LORD for ever: with my mouth will I make known thy faithfulness to all generations.
Psalms 89:1-52. The covenant of promise with David and with Messiah, the antitype to David's seed, Solomon; God's promise of perpetuity (Psalms 89:1-37); the existing state a sad contrast to this (Psalms 89:38-45); prayer to God to remove the contrast (Psalms 89:46-51). The Jewish commentators generally, as Solomon and Aben Ezra, refer the psalm to Messiah.
I will sing of the mercies of the Lord for ever. The speaker is Israel. "The mercies of the Lord" are (Psalms 89:49) "thy former loving-kindnesses which thou swarest unto David in thy truth;" "the sure mercies of David" (Isaiah 55:3).
With my mouth will I make known thy faithfulness to all generations. God's faithfulness to His covenant is made the prominent topic of praise (cf. Psalms 89:2; Psalms 89:5; Psalms 89:8; Psalms 89:24; Psalms 89:33), and forms the ground of the closing prayer. It is strong faith which praises God for His mercy and faithfulness as enduring forever, at a time when, to outward appearance, both have ceased toward His people. The Psalmist resolves to praise Yahweh's 'mercies and faithfulness' forever, because he is convinced they will stand the test.