Verse 21. - It shall be a perpetual statute. This formula usually emphasizes something of solemn importance. In this case, as apparently above in verse 10, the regulations thus enforced might seem of trifling moment. But the whole design of this ordinance, down to its minutest detail, was to stamp upon physical death a far-reaching power of defiling and separating from God, which extended even to the very means Divinely appointed as a remedy. The Jew, whose religious feelings were modeled upon this law, must have felt himself entangled in the meshes of a net so widely cast about him that he could hardly quite escape it by extreme caution and multiplied observances; he might indeed exclaim, unless habit hardened him to it, "Who shall deliver me from the body of this death?"

19:11-22 Why did the law make a corpse a defiling thing? Because death is the wages of sin, which entered into the world by it, and reigns by the power of it. The law could not conquer death, nor abolish it, as the gospel does, by bringing life and immortality to light, and so introducing a better hope. As the ashes of the heifer signified the merit of Christ, so the running water signified the power and grace of the blessed Spirit, who is compared to rivers of living water; and it is by his work that the righteousness of Christ is applied to us for our cleansing. Those who promise themselves benefit by the righteousness of Christ, while they submit not to the grace and influence of the Holy Spirit, do but deceive themselves; we cannot be purified by the ashes, otherwise than in the running water. What use could there be in these appointments, if they do not refer to the doctrines concerning the sacrifice of Christ? But comparing them with the New Testament, the knowledge to be got from them is evident. The true state of fallen man is shown in these institutions. Here we learn the defiling nature of sin, and are warned to avoid evil communications.And it shall be a perpetual statute unto them,.... To the children of Israel, throughout their generations, unto the coming of the Messiah, when the ceremonial law, which stood in divers washings and purifications, was abolished:

that he that sprinkleth the water of separation shall wash his clothes; the priest that sprinkled, according to the Targum of Jonathan, or any other person that did it; so that the same purifying water, which made an unclean person clean, defiled a clean one; for though it was purifying, it had uncleanness in it; having the ashes not only of the cow itself, but of its skin, blood, and dung; and so a lye made of ashes is impure in itself, and yet serves to scour cloth: Ainsworth thinks this signifies the imperfection and insufficiency of legal rites, which, in their greatest virtue, only sanctified to the purifying of the flesh, and left the purifier himself in uncleanness he had not before; by consideration of which, the people might be led to Christ, and his Spirit, for cleansing, Hebrews 9:13 but it rather signifies, that the blood of Christ, which cleanses from all sin, and answers to this purifying water, that its cleansing virtue is owing to Christ being made sin for his people; and that some may be instruments of directing souls to the blood of Christ for cleansing, and yet be defiled themselves: it does not appear that this man, thus unclean, was to have the water of purification sprinkled on him, but was only to wash his clothes; see Revelation 7:14.

and he that toucheth the water of separation shall be unclean until even: but was not clean until he had washed, as Aben Ezra observes, though not expressed; for if one that only sprinkled it had need to be washed, much more one that touched it, and which was unavoidable, if, when he mixed the water and ashes together, he stirred them with his finger; see Gill on Numbers 19:17, though Maimonides (t) understands this of sprinkling and touching the water when there was no necessity for it, when a person was not employed in doing the duty of this law.

(t) Hilchot Parah Adumah, c. 15. sect. 1.