Note: C.H. Spurgeon calls Psalm 89 “the great Covenant Psalm.”
A maskil [probably a literary or musical term] of Ethan the Ezrahite [a contemporary of Solomon (cf. 1 Kings 4:31)].
89:1 I will sing of [note two themes of this song of praise]  the mercies [Heb. “hesed” refers to the Lord’s steadfast, unfailing covenant love; mercies; cf. 2 Sam. 7:15] of the LORD for ever: with my mouth will I make known thy  faithfulness [signifies firmness, steadiness, and certainty] to all generations.
Note: Have you recently experienced discouraging or difficult times? What difference did the reality of God’s faithfulnes make in the way you faced the challenge?
89:2 For I have said, Mercy [“your love” (NIV); in the Bible, love is not emotions but acts of kindness or mercy shown to someone] shall be built up for ever [God’s love is an eternal love]: thy faithfulness shalt thou establish [built] in the very heavens.
89:3 I have made [God made covenant with David; fulfillment of covenant depended on God Himself, not on David or his descendants] a covenant [refers to God’s promise to David in 2 Sam. 7:8-16] with my chosen [David], I have sworn unto David my servant,
89:4 Thy seed [or “offspring”] will I establish for ever [from David on, all of Israel’s legitimate kings would descend from David; David’s greatest descendant would be the Messiah, Jesus Christ], and build up thy throne [David’s God-given role and authority] to all generations. Selah.
89:19 Then thou spakest [to Nathan the prophet] in vision [cf. 2 Sam. 7:4] to thy holy one [perhaps denotes the people of God, the loyal remnant or David himself], and saidst, I have laid help upon one that is mighty; I have exalted one chosen [cf. Acts 13:22] out of the people.
89:20 I have found David my servant; with my holy oil have I anointed [and thus set apart for God’s service; from same root as “Messiah”] him:
89:21 With whom my hand shall be established: mine arm [God was the source of David’s strength] also shall strengthen him.
89:22 [promises of military success (89:22-23)] The enemy shall not exact upon him; nor the son of wickedness afflict him.
89:23 And I will beat down his foes before his face, and plague them that hate him.
89:24 But my faithfulness and my mercy shall be with him: and in my name shall his horn [strength] be exalted.
89:30 If [note condition…] his children [David’s descendants] forsake my law, and walk not in my judgments;
89:31 If [note condition…] they break my statutes, and keep not my commandments;
89:32 Then will I visit [no one can sin with impunity; cf. Col. 3:25] their transgression with the rod [a symbol of authority; an instrument of punishment], and their iniquity with stripes [blows or assaults].
89:33 Nevertheless my lovingkindness will I not utterly take from him, nor suffer my faithfulness to fail.
89:34 My [God drafted and voluntarily entered into the covenant] covenant will I not break, nor alter the thing that is gone out of my lips.