When during the days of the judges the ancient Israelites told Samuel to appoint a king over them, the Lord remarked that the people had rejected Him as their king and Samuel gave a lengthy speech on the dangers of monarchies (1 Sam. 8). For this reason, some people have thought that human kingship is itself not the Lord’s best plan for His people. However, we see that this cannot be the case when we take all of Scripture into account. Long before the people spoke to Samuel, God promised to appoint a king of Israel from the tribe of Judah, and He even established rules by which the king was to govern His people (Gen. 49:8–12; Deut. 17:14–20). Israel’s problem was not that the people wanted a human king; the problem is that they wanted a “king like all the nations” had (1 Sam. 8:5), namely, one who would exalt his own strength, abilities, and glory.
The proper king for Israel had to obey God’s law (Deut. 17:14–20), which ultimately meant glorying in the strength of the Lord, for to glory in anything else is to commit idolatry and break that law. In today’s passage, written by King David, we find the words of the kind of king that Israel was supposed to have—a king who rejoiced in his Lord and not in his own strength. Note how the psalm begins with an affirmation that God and His salvation is what moves David to rejoicing. Here is a king who sought not his own glory but the glory of the Lord (Ps. 21:1).
Verses 2–7 follow with a list of all the blessings conferred upon David, including “length of days forever and ever” (v. 4). Given that David eventually died and his own reign as king of Israel came to an end, we must understand these words and the rest of the psalm as referring finally to the Lord Jesus. When we take that into consideration, we gain great insight into this text. At Christ’s ascension, God the Father met Him with great blessings, bestowing on Him a glorious crown (v. 3; Acts 5:30–31). In saving Him from death through the resurrection, the Father gave glory, splendor, and majesty to Him (Ps. 21:5; Rom. 1:4).
Because of God’s actions in blessing Jesus for trusting in Him, we His people can be confident of Christ’s final victory over all of His and our enemies. Though they plan evil against Him, He will finally vanquish them, and He is even now putting them to flight (Ps. 21:8–12; 1 Cor. 15:25). Jesus alone perfectly gloried in God’s strength, so God will destroy the enemies of His Son and the enemies of all who are in Jesus by faith alone.