Psalm 89 appears in a list of eleven psalms containing major portions that foretell Christ's life, character, ministry, death, or sovereign rulership in the Kingdom of God. This placement situates the psalm within the broader category of Messianic psalms, which the material distinguishes from royal psalms by the extent of their focus on the coming Savior. The discussion develops through an explanation of how such psalms employ the principle of type and antitype, often written about David yet fulfilled more fully in Christ's first or second coming. Psalm 89 is thereby connected to the overall claim that the Psalms form a major repository of prophecies concerning the Messiah, a point reinforced by Christ's statement in Luke 24:44 that the Law, the Prophets, and the Psalms all speak of Him.

Psalm 89 is introduced as the passage that explains the "sure mercies of David" mentioned in Isaiah 55:3, where God promises an everlasting covenant. Since the Old Covenant made with Israel was not everlasting, this promise must extend beyond its original hearers to those who come later, including present-day believers. Psalm 89:19-25 records God speaking of finding His servant David, anointing him, and establishing him with strength against his enemies. While these words were originally addressed to David, they point beyond him to Jesus Christ, with the understanding that those who enter the New Covenant are included in what is being described. The psalm continues in verses 26-29, where the one anointed cries out to God as Father, and God declares He will make him His firstborn, the highest of the kings of the earth, keeping mercy toward him forever and establishing his covenant and his seed permanently. This language moves the identification more clearly toward Jesus Christ as the ultimate recipient of the promise. Verses 33-35 reinforce the permanence of this covenant: God's lovingkindness will not be removed, His faithfulness will not fail, His covenant will not be broken, and He has sworn by His holiness not to lie to David. This passage is connected back to Isaiah 55 to show that the everlasting covenant proposed there is the very covenant described in Psalm 89, and that it lies in the future relative to when Isaiah spoke. This means the exhortation in Isaiah 55 to seek God is aimed at the church—at those who will later be brought into this covenant relationship through Christ. The connection establishes that although the New Covenant has already been made, it is not yet a fully completed matter until believers are actually in God's Kingdom. Isaiah 55, read in light of Psalm 89, therefore functions as a serious call to complete the covenant relationship by living by faith and submitting to God's sovereignty. The broader point drawn from this connection is that entering fully into the promise of Psalm 89—the everlasting covenant, sonship, and enduring inheritance—depends on cooperation with God: seeking Him, hearing Him, and allowing Him to shape one's life. This is presented as the pathway by which believers come to be formed into the image of Jesus Christ, the ultimate heir of the covenant first spoken to David. Psalm 89 thus serves as scriptural proof that the promises given to David were never meant to terminate with him, but were always intended to reach forward into an eternal fulfillment through Christ, in which those who respond in faith are made participants.

Psalm 89 enters the discussion as part of Peter's scriptural argument in Acts 2 that Jesus of Nazareth is both Lord and Christ, the promised Messiah descended from David. After quoting Psalm 132:11-12, which speaks of God swearing to set the "fruit of David's body" upon his throne on condition that his sons keep the covenant, attention turns to Psalm 89:3-4, where God declares, "I have made a covenant with My chosen, I have sworn to My servant David: Your seed I will establish forever, and build up your throne to all generations." This verse reinforces the covenant promise already noted in Psalm 132, using the terms "forever" and "all generations," though these Hebrew expressions are understood not as meaning "without end" in the English sense, but rather "as long as the conditions exist"—suggesting an ongoing line of descendants across successive generations. However, Psalm 89 is shown to move beyond this generational limitation later in the same psalm. Verses 35-37 declare, "Once I have sworn by My holiness; I will not lie to David: His seed shall endure forever, and his throne as the sun before Me; it shall be established forever like the moon, even like a faithful witness in the sky." This language extends the promise far beyond the natural life of mankind on earth, pointing forward into the future Kingdom of God, where the throne of David's seed continues as long as the sun and moon exist. This assurance, taken together with the earlier verses in Psalm 89 and with Psalm 132, along with the prophecy given through Nathan and recorded in II Samuel 7, is presented as the basis by which David himself would have come to understand that God intended not merely a line of successive royal descendants, but one particular descendant—much as the promise to Abraham concerning his "seed" ultimately pointed to a single figure through whom blessing would come, even though the term could also be used collectively. Within Peter's sermon, this Davidic covenant material from Psalm 89, alongside Psalm 132 and Psalm 16, functions as proof that the resurrection and enthronement of Jesus fulfill what David himself foresaw and prophesied. Peter uses this evidence to demonstrate that the eternal throne promised to David's seed could not simply refer to an ordinary succession of kings, since David died and was buried, but must refer to the Messiah who would rise from death and reign forever. Thus Psalm 89 contributes directly to the larger argument of the sermon: that Jesus, crucified by the very people Peter addresses, is in fact the eternal descendant of David destined to sit upon an everlasting throne, thereby confirming His identity as both Lord and Christ and driving home the conviction that leads the hearers to repentance and baptism.