T. Justin Comer

The Necessity of the Incarnation

Most people don’t reject theology—they inherit it. And what we inherit is often fragmented. Priesthood sits in one category, the incarnation in another, the cross in a third, while anthropology lingers off to the side. Each doctrine is explained well enough on its own, but rarely do we ask how they actually hold together. So priesthood becomes a distant religious system tied to ritual and sacrifice. The cross becomes a solution God chose to deal with sin. The incarnation is affirmed, but treated as a prerequisite—something that had to happen so the cross could happen, without asking why it had to happen that way at all.

Everything is true. But it isn’t integrated.

And when theology is fragmented, it reshapes how we see God. The cross begins to feel like a method rather than a revelation—one option among many. We instinctively ask, “Why did God choose this way?” as though other options were available. But that question assumes something Scripture never gives us: that God could have done it differently, that the cross is a decision rather than a disclosure. The deeper question is not about method but nature—not why this way, but what does this reveal about who God is? Because if something truly reveals, it is not arbitrary. It is the thing that makes sense of everything else.

This is where the Epistle to the Hebrews becomes unavoidable. Hebrews does not treat priesthood as a side topic; it uses it as the interpretive key for understanding Christ—not only what He did, but who He is. And once that framework is followed, a conclusion emerges that most of us have never fully pressed: if priesthood is what Hebrews says it is, and if Christ is truly the High Priest it reveals Him to be, then the incarnation was not optional and the cross was not a chosen method. They were necessary—not because God was constrained from the outside, but because He is consistent with Himself. This is not ultimately a discussion about religious systems. It is a question about God. If priesthood reflects His nature, then the incarnation and the cross are not arbitrary acts in history, but the inevitable expression of who He is.

That claim must be grounded in the text. And no text presses it more directly than Hebrews. The letter is written to people already shaped by temple, sacrifice, covenant, and priesthood, and it reinterprets all of it in light of Christ. From the opening lines, the argument ascends: “Long ago… God spoke… but in these last days He has spoken to us by His Son” (Hebrews 1:1–2). Everything before was partial; now something final has appeared—not merely another message, but a person. Christ is shown to be greater than angels (Hebrews 1–2), greater than Moses (Hebrews 3–4), and greater than Joshua, bringing a deeper rest (Hebrews 4). Each comparison strips away reliance on the old framework, preparing for the true claim: “Every high priest chosen from among men is appointed to act on behalf of men in relation to God…” (Hebrews 5:1).

That is the turn. Not just who Christ is greater than, but what He is.

From there, everything orbits around His priesthood. Hebrews 5–7 establishes its nature, Hebrews 8 unfolds its covenant, and Hebrews 9–10 brings the argument to its climax in His once-for-all sacrifice. The structure is precise: by the time the conclusion arrives, it does not feel like a leap but an inevitability. And within that framework, one detail becomes decisive. Before Hebrews explains what Christ offers, it defines what a priest must be.

“Taken from among men.”

Priesthood begins with identity, not function. Before a priest offers anything, he must be something—one of the people he represents. This is not incidental or cultural; it is definitional. Representation is participatory. A priest does not stand over the people as something different from them, but with them as one of them. You cannot mediate from the outside. You cannot represent what you do not share.

That requirement creates a tension at the center of the New Testament. The same Scriptures that speak of a coming priest also speak of a coming king—exalted, seated at God’s right hand (Psalm 110:1), ruling beyond Israel. Is He truly human, or something greater? Hebrews does not resolve the tension by collapsing one side into the other; it intensifies it. “He had to be made like His brothers in every respect… so that He might become a merciful and faithful high priest” (Hebrews 2:17). Not similar. Not partial. In every respect.

The requirement is absolute. If He is to be priest, He must fully share in the nature of those He represents. Which means the incarnation is not a theological curiosity. It is demanded by the structure. If Christ does not become human, He cannot be priest. If He cannot be priest, He cannot mediate. The incarnation is not God entering creation as an option among many—it is God meeting the requirement of priesthood through participation.

But Hebrews does not leave priesthood confined to familiar categories. It introduces a figure who disrupts them entirely: Melchizedek. “You are a priest forever, after the order of Melchizedek” (Hebrews 5:6; Psalm 110:4). This priest-king appears in Genesis 14 without genealogy, without origin, without explanation, yet blesses Abraham and receives tithes. Hebrews seizes on that absence: “without father or mother… resembling the Son of God” (Hebrews 7:3). The point is not that Melchizedek is eternal, but that Scripture presents him without the markers that normally define priesthood.

If priesthood were fundamentally about lineage, he would be disqualified. But he isn’t. Which means priesthood is not grounded in genealogy, but in something deeper. Hebrews makes this explicit: “our Lord was descended from Judah… and in connection with that tribe Moses said nothing about priests” (Hebrews 7:14). By every legal measure, Jesus should not qualify. Wrong tribe. No lineage. And yet He is the High Priest. The Levitical system is not the foundation—it is a shadow, pointing beyond itself to a deeper reality.

Priesthood, then, is not merely institutional. It is ontological. Not simply about where one comes from, but what one is. Christ’s priesthood is not something He steps into; it corresponds to His being. Which reframes the question. It is not only why the priest must be human, but what kind of mediation requires both shared humanity and something more.

At its core, priesthood is not defined by ritual but by mediation. “Appointed to act on behalf of men in relation to God” (Hebrews 5:1). A priest stands in the space where God and humanity meet. Sacrifice, intercession, and representation are expressions of that role, but not its essence. The essence is mediation—the bringing together of realities that, left to themselves, do not meet. This is why the priest must share in humanity and yet correspond to God. Priesthood lives in that tension.

And once defined this way, the question reaches backward. Is priesthood merely a response to sin, or is it embedded in creation itself?

Genesis answers.

“The LORD God took the man and put him in the garden… to work it and keep it” (Genesis 2:15). The language is priestly. The same verbs later describe tabernacle service (Numbers 3:7–8). Eden is not ordinary land—it is sacred space, a place where God dwells with man. Adam stands within it not merely as a cultivator, but as a mediator. He represents creation before God and extends God’s order into creation. This is priesthood before sacrifice, before atonement, before anything needed to be fixed.

Priesthood does not originate in sin. It originates in design.

Humanity was created to live at the intersection of heaven and earth, bearing God’s image through representative rule (Genesis 1:26–28). The fall fractures that reality, expelling humanity from sacred space (Genesis 3:23–24). What was once natural becomes restricted. Sacrifice enters. Priests are appointed—not to create something new, but to preserve fragments of what was lost. When Hebrews presents Christ as High Priest, it is not introducing a new concept, but restoring an original one.

That restoration cannot be understood if priesthood is thought to begin with humanity. Humanity reflects what originates in God. If we are priestly, and if we bear His image, then priesthood reflects something true about Him. Not as a role He adopted, but as an expression of His nature. Scripture consistently presents God as One who draws near, who reveals, who mediates. “The Word became flesh and dwelt among us” (John 1:14). What appears in creation as priesthood is the echo of something eternal.

Christ does not step into a foreign role. He reveals what was always true. “The exact imprint of His nature” (Hebrews 1:3). When He mediates, reveals, and gives Himself, He acts in perfect alignment with who He is. Which means the cross is not simply something God does—it begins to look like something He must do, not by external constraint, but by internal consistency.

Hebrews maintains a crucial distinction. Christ does not formally function as High Priest before the cross; that role is inaugurated through sacrifice (Hebrews 9:12). Yet even before the cross, He mediates revelation, bringing the invisible into visibility (John 1:18; Hebrews 1:3). The priestly nature is not introduced at the cross—it is expressed through it. What is eternally true of Him becomes enacted in history.

The cross is where everything converges—the eternal and the temporal, the divine and the human. It is not merely where Christ does something priestly, but where He becomes High Priest in the full, enacted sense by entering into the condition that requires mediation. And once God truly enters human nature, the cross is no longer one possible outcome. It is inevitable. Mediation within a fractured world becomes costly. It becomes sacrificial. It becomes blood.

By the time Hebrews reaches its climax, the conclusion is unavoidable. Christ “entered once for all… by means of His own blood” (Hebrews 9:12). Not into earthly shadows, but into the reality they pointed toward. He offers not something external, but Himself. The repetition ends because the necessary sacrifice has been given. “By a single offering He has perfected for all time” (Hebrews 10:14). The priest sits (Hebrews 10:12), not in inactivity, but in completion.

The cross is where priesthood reaches its full expression—no longer partial, repeated, or symbolic, but complete. It is not one way God chose to accomplish redemption. It is the only way consistent with what priesthood is—and therefore, the only way consistent with who God is.

Which means the question is no longer how the cross saves, but what it shows. It reveals God. Not merely a mechanism, but a nature. The cross is not a strategy; it is the expression of a priest who gives Himself. And if Christ is the exact imprint of God’s nature, then what we see at the cross is what God is like: self-giving, mediatory, near.

God does not remain outside the problem. He enters it.

He does not mediate from a distance. He mediates from within.

He does not give something other than Himself. He gives Himself.

And once that is seen, the conclusion cannot be avoided. The cross was not one option among many. It was the only outcome consistent with who He is. Not an exception in the story, but its clearest expression. And if that is true, then priesthood is not a category to study at a distance, but a reality we were created to participate in—because the same pattern seen in Christ is the pattern humanity was always meant to reflect.