Matthew Henry - Complete Commentary
 1   We have here the law concerning the ceremonial uncleanness that was contracted by running issues in men. It is called in the margin (Lev 15:2) the running of the reins: a very grievous and loathsome disease, which was, usually the effect and consequent of wantonness and uncleanness, and a dissolute course of life, filling men's bones with the sins of their youth, and leaving them to mourn at the last, when all the pleasures of their wickedness have vanished, and nothing remains but the pain and anguish of a rotten carcase and a wounded conscience. And what fruit has the sinner then of those things whereof he has so much reason to be ashamed? Roma 6:21. As modesty is an ornament of grace to the head and chains about the neck, so chastity is health to the navel and marrow to the bones; but uncleanness is a wound and dishonour, the consumption of the flesh and the body, and a sin which is often its own punishment more than any other. It was also sometimes inflicted by the righteous hand of God for other sins, as appears by David's imprecation of a curse upon the family of Joab, for the murder of Abner. 2Sam 3:29, Let there not fail from the house of Joab one that hath an issue, or is a leper. A vile disease for vile deserts. Now whoever had this disease upon him, 1. He was himself unclean, Lev 15:2. He must not dare to come near the sanctuary, it was at his peril if he did, nor might he eat of the holy things. This signified the filthiness of sin, and of all the productions of our corrupt nature, which render us odious to God's holiness, and utterly unfit for communion with him. Out of a pure heart well kept are the issues of life (Prov 4:23), but out of an unclean heart comes that which is defiling, Matt 12:34, Matt 12:35. 2. He made every person and thing unclean that he touched, or that touched him, Lev 15:4-Lev 15:12. His bed, and his chair, and his saddle, and every thing that belonged to him, could not be touched without a ceremonial uncleanness contracted, which a man must remain conscious to himself of till sunset, and from which he could not be cleansed without washing his clothes, and bathing his flesh in water. This signified the contagion of sin, the danger we are in of being polluted by conversing with those that are polluted, and the need we have with the utmost circumspection to save ourselves from this untoward generation. 3. When he was cured of the disease, yet he could not be cleansed from the pollution without a sacrifice, for which he was to prepare himself by seven days' expectation after he was perfectly clear from his distemper, and by bathing in spring water, Lev 15:13-Lev 15:15. This signified the great gospel duties of faith and repentance, and the great gospel privileges of the application of Christ's blood to our souls for our justification and his grace for our sanctification. God has promised to sprinkle clean water upon us, and to cleanse us from all our filthiness, and has appointed us by repentance to wash and make ourselves clean: he has also provided a sacrifice of atonement, and requires us by faith to interest ourselves in that sacrifice; for it is the blood of Christ his Son that cleanses us from all sin, and by which atonement is made for us, that we may have admission into God's presence and may partake of his favour.

 19   This is concerning the ceremonial uncleanness which women lay under from their issues, both those that were regular and healthful, and according to the course of nature (Lev 15:19-Lev 15:24), and those that were unseasonable, excessive, and the disease of the body; such was the bloody issue of that poor woman who was suddenly cured by touching the hem of Christ's garment, after she had lain twelve years under her distemper, and had spent her estate upon physicians and physic in vain. This made the woman that was afflicted with it unclean (Lev 15:25) and every thing she touched unclean, Lev 15:26, Lev 15:27. And if she was cured, and found by seven days' trial that she was perfectly free from her issue of blood, she was to be cleansed by the offering of two turtle-doves or two young pigeons, to make an atonement for her, Lev 15:28, Lev 15:29. All wicked courses, particularly idolatries, are compared to the uncleanness of a removed woman (Ezek 36:17), and, in allusion to this, it is said of Jerusalem (Lam 1:9), Her filthiness is in her skirts, so that (as it follows, Lev 15:17) she was shunned as a menstruous woman.
I. The reasons given for all these laws (which we are ready to think might very well have been spared) we have, Lev 15:31. 1. Thus shall you separate the children of Israel (for to them only and their servants and proselytes these laws pertained) from their uncleanness; that is, (1.) By these laws they were taught their privilege and honour, that they were purified unto God a peculiar people, and were intended by the holy God for a kingdom of priests, a holy nation; for that was a defilement to them which was not so to others. (2.) They were also taught their duty, which was to preserve the honour of their purity, and to keep themselves from all sinful pollutions. It was easy for them to argue that if those pollutions which were natural, unavoidable, involuntary, their affliction and not their sin, rendered them for the time so odious that they were not fit for communion either with God or man, much more abominable and filthy were they if they sinned against the light and law of nature, by drunkenness, adultery, fraud, and the like sins, which defile the very mind and conscience. And, if these ceremonial pollutions could not be done away but by sacrifice and offering, something greater and much more valuable must be expected and depended upon for the purifying of the soul from the uncleanness of sin. 2. Thus their dying in their uncleanness by the hand of God's justice, if while they were under any of these defilements they should come near the sanctuary, would be prevented. Note, It is a dangerous thing to die in our uncleanness; and it is our own fault if we do, since we have not only fair warning given us, by God's law, against those things that will defile us, but also such gracious provision made by his gospel for our cleansing if at any time we be defiled. 3. In all these laws there seems to be a special regard had to the honour of the tabernacle, to which none must approach in their uncleanness, that they defile not my tabernacle. Infinite Wisdom took this course to preserve in the minds of that careless people a continual dread of, and veneration for, the manifestations of God's glory and presence among them in his sanctuary. Now that the tabernacle of God was with men familiarity would be apt to breed contempt, and therefore the law made so many things of frequent incidence to be ceremonial pollutions, and to involve an incapacity of drawing near to the sanctuary (making death the penalty), that so they might not approach without great caution, and reverence, and serious preparation, and fear of being found unfit. Thus they were taught never to draw near to God but with an awful humble sense of their distance and danger, and an exact observance of every thing that was required in order to their safety and acceptance.
II. And what duty must we learn from all this? 1. Let us bless God that we are not under the yoke of these carnal ordinances, that, as nothing can destroy us, so nothing can defile us, but sin. Those may now partake of the Lord's supper who durst not then eat of the peace-offerings. And the defilement we contract by our sins of daily infirmity we may be cleansed from in secret by the renewed acts of repentance and faith, without bathing in water or bringing an offering to the door of the tabernacle. 2. Let us carefully abstain from all sin, as defiling to the conscience, and particularly from all fleshly lusts, possessing our vessel in sanctification and honour, and not in the lusts of uncleanness, which not only pollute the soul, but war against it, and threaten its ruin. 3. Let us all see how indispensably necessary real holiness is to our future happiness, and get our hearts purified by faith, that we may see God. Perhaps it is in allusion to these laws which forbade the unclean to approach the sanctuary that when it is asked, Who shall stand in God's holy place? it is answered, He that hath clean hands and a pure heart (Pss 24:3, Pss 24:4); for without holiness no man shall see the Lord.