A unique quality that distinguishes Jesus as the supreme ruler is His function as a king-priest. While these two offices operated separately in ancient Israel—to administer justice in the nation and to implement accountability between the two offices (Deut 17; 2 Kgs 22–23)—in Messiah Jesus these two offices of authority converged.

This is precisely what Yahweh reveals to David concerning the Messiah in Psalm 110. First, that the Messiah is the supreme king (v. 1); and second, that the Messiah is the supreme priest (v. 4). Indeed, the psalm articulates that the Messiah is uniquely the supreme king-priest.

The Messiah as the Supreme King

The first decree that God reveals to David in Psalm 110:1 is that the Messiah is the supreme king. Four elements in the psalm affirm this.

First, David himself acknowledges that the Messiah is greater than he, as he exclaims: “The LORD [i.e., Yahweh] says to my Lord [i.e., Messiah].” As the king of Israel, David was the most powerful person in the land. However, when David referred to the Messiah as “my Lord,” David professed that the Messiah was greater than he. This is precisely the point Jesus made to the Pharisees in Matthew 22:45, when he said: “If then David calls him Lord, how is he his son?”

Second, Yahweh exalts the Messiah when Yahweh declares to him: “Sit at my right hand…” To sit at the right hand of Yahweh meant to experience the honor, power, and intimacy with God that neither David nor any other king would ever experience. Peter argued this in Acts 2:34–35: “For David did not ascend into the heavens, but he himself says, ‘The Lord said to my Lord, “Sit at my right hand, until I will make your enemies your footstool” ’ ” (see Heb 1:3, 13).

Third, Yahweh promises to make the Messiah the ultimate conqueror, when He states: “until I will make your enemies your footstool.” This image of victory is reinforced in v. 2 with the remarks: “The LORD sends forth from Zion your mighty scepter. Rule in the midst of your enemies!” To make a footstool of an enemy meant to subjugate that enemy to the uttermost and to display absolute triumph. Thus when Joshua conquered his enemies, he instructed the Israelite leaders to place their feet on the necks of their enemy-kings (Josh 10:24).

Finally, the psalm depicts the Messiah to be supreme in that the Messiah is portrayed as a cosmic conqueror. The statement “I will make your enemies your footstool” is unique in the Old Testament. But a statement similar to this appears in Genesis 3:15, when God proclaims to the serpent: “‘I will make enmity between you and the woman, and between your offspring and her offspring…’”

The relationship between these two statements—Genesis 3:15 and Psalm 110:1—is an inverse relationship, but the implications are momentous. In Genesis 3:15, God announces the inception of enmity: I will make enmity! But in Psalm 110:1, God declares the annihilation of enemies: I will make your enemies your footstool. Psalm 110 promises to undo what was done in Genesis 3. The Messiah will unmake the enmity that was made in the beginning. Put plainly, the Messiah will reverse the curse (1 Cor 15:25; Rom 16:20). The priesthood of the Messiah belonged to a “better covenant”

Psalm 110, in summary, indicates that the Messiah will conquer his enemies, overcome the enmity that emerged at the fall, and reign as the ultimate king. Those who oppose him will be defeated, while those who submit to him will serve him willingly (v. 3). According to the first decree, then, the Messiah is the supreme king.

The Messiah as the Supreme Priest

The second decree that God reveals to David in Psalm 110:4 is that, in addition to being the supreme king, the Messiah is also the supreme priest. He distinguishes himself as the supreme priest in two respects.

An Eternal Priest

First, the Messiah is an eternal priest, not a temporary priest. The function of the Israelite priest was to mediate between God and Man throughout his life (Lev 1–7; 16). When the priest died, he was succeeded by his son, generation after generation (Exod 28:40–41). However, while every typical Israelite priest did indeed die, the Messiah would overcome death. Consequently, he would function as a priest forever.

Psalm 110, in fact, demonstrates this by means of analogy, comparing the Messiah to Melchizedek. Because the Old Testament presents Melchizedek specifically and solely as a king-priest—providing neither his genealogy that preceded him, nor his genealogy that succeeded him—Melchizedek is forever remembered as a king-priest (Gen 14). Thus as Melchizedek is etched in the memory of history as an “eternal” priest, so the Messiah is an eternal priest (Heb 7:3). The difference, however, is that the Messiah is actually and in fact truly an eternal priest.

A Melchizedekian Priest

Second, the Messiah is a priest according to the order of Melchizedek, not a priest from the line of Levi through the priesthood of Aaron.

All the priests who inherited the priesthood through Levi and Aaron were appointed to the priesthood by their human birth. The Messiah, however, is appointed to the priesthood directly by God. Psalm 110:4 explicitly states: “The LORD has sworn and will not change his mind, ‘You are a priest forever after the order of Melchizedek.’ ” The Messiah is installed into priesthood by an oath of God, not by human heritage (Heb 5:1–5, 10; 7:20–21). God transcends the Levitical lineage marked by generational death, and replaces the priests of Aaron with the Messiah who alone would serve as a priest forever.

Explaining the implications of this, Hebrews 7:23–25 states that the Messiah is therefore “able to save to the uttermost those who draw near to God through him, since he always lives to make intercession for them.” In other words, the Messiah is able to lead the individual through every trial and temptation until the very end to victory.

Thus, in addition to the first decree—that the Messiah is the supreme king—the second decree declares that the Messiah is also the supreme priest.

The Messiah as the Supreme King-Priest

An inevitable and a significant conclusion of these two decrees is that the Messiah is both a king and a priest. Consequently, the authority of the king and the authority of the priest converge into one jurisdiction within the sovereign reign of this ideal ruler.

The ultimate ruler would fulfill these two roles in one person—the ideal ruler would be a king-priestThis, however, is problematic. To a typical ancient Israelite, the combined office of a king-priest was inconceivable. God had established that kings came from the line of Judah, while priests came from the line of Levi (Gen 49; 1 Sam 13; 15; 28; 2 Sam 2:1–4; Exod 28–29; and see Deut 17; 2 Chr 26:16–23). Indeed, Saul forfeited his kingship because he offered a sacrifice that he was not fit to offer (1 Sam 13:8–13; see 2 Chr 26:16–23). And Hebrews 7:13 explains: “For [Jesus] the one of whom these things are spoken belonged to another tribe [Judah, not Levi!], from which no one has ever served at the altar.” That is to say, prior to Jesus no one from the line of Judah had ever served as a priest, because the function of the priest belonged to the line of Levi. In the Mosaic Covenant, then, a single individual could not serve both as a king and as a priest.

Why then does God reveal to David that the ideal ruler, the Messiah, would do something that was prohibited—that he would be both a king and a priest?

D.A. Carson suggests that God gives this revelation, because despite the legal prohibition to combine these two offices within the contours of the Mosaic Covenant, David still understood that the ultimate ruler would fulfill these two roles in one person—the ideal ruler would be a king-priest (Carson, Scriptures Testify about Me, 154–164). Carson explains that when David began to establish his throne and the priestly system in Jerusalem (2 Sam 2–6), David reflected on the kingship of Melchizedek (Gen 14; and see Deut 17)—a king of Salem (Jerusalem?)—and David realized that Melchizedek manifested a superior status to that of a mere king because he was both a king and a priest (Carson, Scriptures Testify about Me, 164). And though David could offer sacrifices from time to time (2 Sam 6:12–15), he could never be an actual priest, let alone, a high priest (see Heb 7:13).

As David contemplated on this reality, Carson proposes, God gave David a revelation to assure David that while David himself could not be the ideal ruler, the Messiah would, in fact, be this ideal ruler, for he would function as a king-priest.

But how could this even take place since the Mosaic Covenant prohibits such a function? Just so! This could be possible only if God were to institute another covenant—a new covenant. And this is what Hebrews indicates—that the priesthood of the Messiah belonged to a “better covenant” (Heb 7:17–22). In the new covenant, therefore, the Messiah Jesus would be able to be both a priest and a king.

Yet rather than forfeiting his kingship in this role as a king-priest—as was the case with Saul—the Messiah would instead achieve world dominion. Psalm 110:5–6 exclaims that the Messiah will shatter kings, judge the nations, and shatter the head over the wide earth (i.e., the unjust governance in the world; cf. Gen 3:15). And according to v. 7, the Messiah will lift up his head in triumph.

The Messiah Jesus as Our King-Priest

The implications of the Messiah’s unique status as a king-priest are significant. As king-priest, the Messiah is able to rule over the people both on a horizontal level and on a vertical level. As king, He would govern the people with respect to the political domain, and as priest He would serve the people with respect to the spiritual domain, mediating between the people and God.

Indeed, the author of Hebrews attributes both of these functions to Jesus. Hebrews 1:8 asserts: “But of the Son he says, ‘Your throne, O God, is forever and ever, the scepter of uprightness is the scepter of your kingdom.’ ” And 2:17 states: “Therefore he [Jesus] had to be made like his brothers in every respect, so that he might become a merciful and faithful high priest in the service of God, to make propitiation for the sins of the people.”

Both of these functions are, therefore, fulfilled in our supreme king-priest Jesus.