The Gospel According to Leprosy Text: Leviticus 13:9-17
Introduction: God's Diagnostic Manual
We come this morning to a passage in Leviticus that makes modern Christians nervous. It is full of priests, skin diseases, raw flesh, and declarations of "unclean." Our temptation is to avert our eyes, to flip past these chapters in a hurry to get to the more "spiritual" parts of the Bible. We treat it like a medical textbook that is bizarrely out of date. But in doing this, we make a profound mistake. We fail to understand that the God who wrote the Gospel of John is the same God who wrote the book of Leviticus. And He does not waste ink.
These laws concerning leprosy are not primarily about dermatology. They are a series of high-definition, Technicolor, 3-D object lessons about the nature of sin. Leprosy in the Bible is a physical picture of a spiritual reality. It is sin in slow motion. It is a walking death, a visible representation of the corruption that festers within every human heart apart from the grace of God. It isolates, it defiles, it spreads, and it ultimately consumes. And just as the priest was the one designated by God to diagnose and declare a man a leper, so the ministers of the Word are tasked with diagnosing and declaring the spiritual state of men.
But there is a startling paradox in this passage, one that turns all our human wisdom on its head. It is a paradox that contains the very heart of the gospel. We are going to see that a little bit of leprosy, a suspicious patch with some raw flesh, makes a man unclean. But a man completely covered in it, head to toe, with no healthy skin remaining, can be declared clean. This is offensive to our sensibilities. It runs contrary to all our bootstrap moralities and self-improvement projects. And that is precisely the point. God has structured His law to demolish our self-righteousness and to drive us to the only one who can truly cleanse us. This passage is a wrecking ball to our pride, and a signpost pointing directly to the cross of Jesus Christ.
The Text
"When the infection of leprosy is on a man, then he shall be brought to the priest. The priest shall then look, and if there is a white swelling in the skin, and it has turned the hair white, and there is raw flesh still alive in the swelling, it is a chronic leprosy on the skin of his body, and the priest shall pronounce him unclean; he shall not isolate him, for he is unclean. But if the leprosy breaks out farther on the skin, and the leprosy covers all the skin of him who has the infection from his head even to his feet, as far as the priest can see, then the priest shall look, and behold, if the leprosy has covered all his body, he shall pronounce clean him who has the infection; it has all turned white, and he is clean. But whenever raw flesh appears on him, he shall be unclean. And the priest shall look at the raw flesh, and he shall pronounce him unclean; the raw flesh is unclean; it is leprosy. Or if the raw flesh turns again and is changed to white, then he shall come to the priest, and the priest shall look at him, and behold, if the infection has turned to white, then the priest shall pronounce clean him who has the infection; he is clean."
(Leviticus 13:9-17 LSB)
The Priest's Examination (vv. 9-11)
The process begins with a man under suspicion being brought to the priest.
"When the infection of leprosy is on a man, then he shall be brought to the priest. The priest shall then look, and if there is a white swelling in the skin, and it has turned the hair white, and there is raw flesh still alive in the swelling, it is a chronic leprosy on the skin of his body, and the priest shall pronounce him unclean; he shall not isolate him, for he is unclean." (Leviticus 13:9-11)
Notice first that the diagnosis of sin is not a private affair. The man is brought to the priest. This is a corporate matter. The holiness of the camp, the purity of God's people, is at stake. In the same way, the church is not a collection of disconnected individuals. We are a body, and sin is a contagion that affects the whole. The elders of a church, functioning as new covenant priests, are charged with the oversight of the flock's spiritual health.
The priest's job is to look. He is not a healer; he is a diagnostician. He applies the objective standard of God's law to the man's condition. He looks for specific signs: a white swelling, white hair, and "raw flesh still alive in the swelling." This "raw flesh" is the key indicator here. It represents active, living corruption. It is a picture of sin that is still fighting, still festering, still trying to appear as though it were healthy life. This is the man who is trying to manage his sin. He has a veneer of righteousness, but underneath, there is a secret, unmortified corruption. He is a whited sepulcher, fair on the outside, but full of dead men's bones within.
When the priest sees this raw flesh, this active rebellion, his duty is clear. He must "pronounce him unclean." This is a declarative act. The priest does not make the man unclean; he declares him to be what he already is. This is the function of the law. The law cannot save; it can only condemn. It holds up God's perfect standard and says, "You are unclean." It shuts every mouth and makes the whole world accountable to God (Romans 3:19). The man is so obviously unclean that he does not even need to be quarantined for observation. He is a chronic case. He is to be put out of the camp, separated from the fellowship of God's people.
The Paradox of Total Corruption (vv. 12-13)
Now the text takes a turn that is utterly confounding to human logic.
"But if the leprosy breaks out farther on the skin, and the leprosy covers all the skin of him who has the infection from his head even to his feet, as far as the priest can see, then the priest shall look, and behold, if the leprosy has covered all his body, he shall pronounce clean him who has theinfection; it has all turned white, and he is clean." (Leviticus 13:12-13 LSB)
This is the heart of the matter. If the disease spreads and covers his entire body, turning him completely white, the priest pronounces him clean. How can this be? It is because the man has stopped pretending. There is no more "raw flesh." There is no part of him pretending to be healthy. He is utterly and completely corrupt, and he knows it. The disease has done its full work, and in a sense, has burned itself out. The man is a walking monument to his own defilement. He has no ground for self-righteousness left. He cannot point to a single spot on his body and say, "At least this part is okay."
This is a perfect illustration of the doctrine of justification by faith alone. A man is not declared righteous by God because he has a little bit of sin here, but a lot of good deeds over there. He is not justified because his good outweighs his bad. That man, the one with the "raw flesh" of his own righteousness, is unclean. The man who is justified is the one who comes to God with nothing in his hands to bring. He is the one who cries out with Isaiah, "Woe is me! For I am lost; for I am a man of unclean lips" (Isaiah 6:5). He is the tax collector who beats his breast and says, "God, be merciful to me, a sinner!" (Luke 18:13). He is the one who agrees with God's diagnosis of his total depravity. He is leprous from head to foot.
When a man comes to this point of utter spiritual bankruptcy, when he abandons all pretense of his own goodness, God does a scandalous thing. He declares that man to be clean. He pronounces him righteous. Not because the man has become inherently righteous, but because he has stopped trusting in his own flesh and is now in a position to be clothed in a righteousness that is not his own. The white of the leprosy, covering him completely, becomes a picture of the imputed righteousness of Christ that covers the believer completely.
The Return of Raw Flesh (vv. 14-17)
The passage concludes by reinforcing this central principle.
"But whenever raw flesh appears on him, he shall be unclean. And the priest shall look at the raw flesh, and he shall pronounce him unclean; the raw flesh is unclean; it is leprosy. Or if the raw flesh turns again and is changed to white, then he shall come to the priest, and the priest shall look at him, and behold, if the infection has turned to white, then the priest shall pronounce clean him who has the infection; he is clean." (Leviticus 13:14-17 LSB)
The danger is always the return of the "raw flesh." What does this represent for the Christian? It represents the return of self-righteousness. It is the attempt to base one's standing with God on one's own performance. It is the Galatian error. After being declared clean by grace, through faith, the Christian can be tempted to start relying on his own efforts to maintain that cleanness. He starts to think, "Look at this little patch of healthy flesh. I produced this. God must be pleased with me because of this." The moment that happens, the moment our confidence shifts from Christ's work for us to our work for Him, we are, in that respect, unclean. The raw flesh of human effort and pride is always unclean in God's sight.
The solution is not to try harder. The solution is to confess that raw flesh for what it is: leprosy. It is to come back to the priest, to the Word of God, and have that self-righteousness covered over once again by the declaration of the gospel. When the raw flesh "is changed to white," when we repent of our pride and trust once more in Christ alone, we are again pronounced clean. Our entire Christian life is a cycle of this. We are constantly tempted to let some raw flesh of pride appear. And we must constantly be driven back to the cross, where our leprous flesh is covered by the pure white robes of Christ's righteousness.
Our Great High Priest
This entire Levitical procedure is a shadow, and the substance is Christ. The Old Testament priest could only look and declare. He could diagnose the disease, but he could not cure it. He could pronounce a man unclean, or, in this strange case, pronounce a totally corrupt man clean, but he could not change the man's underlying condition.
But we have a Great High Priest, Jesus Christ, who does what the Levitical priests never could. He does not just look at the leper; He touches the leper (Matthew 8:3). According to the law, touching a leper would make you unclean. But when Jesus, the holy one of God, touches the unclean, He does not become defiled. The uncleanness is swallowed up by His perfect holiness. He does not just declare the leper clean; He makes him clean. He says, "I will; be clean." And immediately the leprosy is gone.
The gospel is this: We are all born with leprosy of the soul. Some of us try to hide it, to manage it, to keep some "raw flesh" of our own goodness on display. And in that state, we are utterly unclean, outside the camp, and without hope. The law comes and acts as the priest, exposing our condition and pronouncing the sentence of death. It shows us that we are covered, head to foot, in the disease.
But this is where grace enters. When we are brought to the end of ourselves, when we acknowledge our total uncleanness, our High Priest Jesus Christ does not cast us out. He reaches out and touches us. He takes our leprosy upon Himself. On the cross, He was made sin for us (2 Corinthians 5:21). He became the ultimate leper, cast out of the camp, bearing our uncleanness in His own body. And in exchange, He gives us His perfect health, His perfect cleanness. He covers us from head to foot in His own righteousness.
Therefore, do not trust in your raw flesh. Do not take pride in your own spiritual progress. That way lies defilement. Rather, confess your total leprosy. Come to the Great Physician with nothing but your disease. Let Him cover you completely. For the man who is only a little bit leprous is unclean, but the man who is nothing but a leper, and who casts himself on the mercy of God in Christ, is the one who hears the glorious, final, and irreversible verdict: "He is clean."