Numbers 19:3. Unto Eleazar— Not Aaron himself, because, by being employed in the following work, he would have been defiled: a thing which, in all cases, he was to avoid. Other reasons are given for this employment of Eleazar; but, perhaps, we may truly say with Spencer, that the cause of this precept arose from some peculiar circumstance of that time, which antiquity has totally obscured and hid from us.

Numbers 19:4. Directly before the tabernacle of the congregation— Towards the Tabernacle of Meeting, Nold. 833.

Numbers 19:6. The priest shall take cedar-wood, and hyssop, &c.— See Leviticus 14:4. The Apostle, Heb 9:19 mentions scarlet wood and hyssop as used by Moses himself when he sprinkled the book of the covenant, &c. with the blood of the sacrifice; and therefore these things, which appear to have been used of old, as cleansers either of inward or outward filth, are ordered here to be burnt with the ashes of the heifer, which were to be mingled with the water of purification, as proper to denote its virtue to cleanse from legal pollutions those who were sprinkled with it.

Numbers 19:7. The priest shall wash his clothes— See Leviticus 24:23; Leviticus 24:23. Bishop Patrick says, some may think it strange, that the same thing should both cleanse and pollute: but this is agreeable to the notion of all expiatory sacrifices; which, though they purified those for whom they were offered, were themselves impure, because the sins of men were, in a manner, transferred to them.

Numbers 19:9. A man that is clean— i.e. free from any legal defilement—shall gather up the ashes; which, being taken up, were pounded and sifted, as the Jews tell us:—and it shall be kept; i.e. according to some, not for the use of that generation only, but for posterity also: for ashes, being the remainder of bodies perfectly dissolved or corrupted, are not capable of a second corruption, and so, being preserved through ages for the purposes of legal purification, till the whole stock of them was exhausted, they became a proper emblem of the everlasting efficacy of Christ's blood to purify the conscience from dead works; (Hebrews 9:13-14.); for the Jews tell us, that the ashes of one heifer was kept so long, that only nine in all were killed for this purpose while their state lasted: but this tradition of theirs, like most others, has little countenance from reason. St. Jerome and others, on the contrary, are of opinion, that the red heifer was slain every year; and indeed it is hardly conceivable, that fewer, at least, than one every year, should suffice to furnish ashes to expiate the ordinary defilements of the whole body of the people. These ashes were to be kept for a water of separation; i.e. as appears from Num 19:17 to be put into water, and so applied to the cleansing of those who were separated from the congregation for legal pollutions; and thus it was to be a purification for sin, or, according to the Hebrew, a sin-offering; an expiation for sin; see ch. Numbers 8:7.
Some of the Jews ascribed a purifying virtue to this consecrated water; but those who understood the true intention of Moses' law considered this in no other light, than as an instituted means to absolve them from legal or ceremonial defilement, which, like the rest of their washings, purifications, and sacrifices, served to represent moral purity, and the necessity of being cleansed by repentance from all filthiness of flesh and spirit, in order to a participation of the divine favor and forgiveness. This moral purpose is much more fully enforced upon Christians, by the death of Christ: For if (says the Apostle) the blood of bulls and goats, and the ashes of an heifer, sprinkling the unclean, sanctifieth to the purifying of the flesh; how much more shall the blood of Christ, who through the eternal spirit offered himself without spot to God, purge your conscience from dead works, to serve the living God?
REFLECTIONS.—The intention of this ceremony was, to purify from ceremonial uncleanness, and to be typical of that sprinkling of the blood of Jesus which really purges the conscience from dead works. The whole was a shadow of Him that was to come. The spotless purity of our divine Lord, when he offered himself a sacrifice for us, is here prefigured. He was red in his apparel, when he trod the wine-press alone, and when he died weltering in his blood. No yoke bound him to the dreadful service; freely he offered himself to bear the sins of many. At once the priest and sacrifice, he offered up his body on the tree, like to an unclean thing, because the Lord had laid on him the iniquity of us all; he suffered without the camp, and from the cross looked up to heaven, sprinkling his blood as it were before the door of the heavenly sanctuary. The fierceness of the fire, and the bitter hyssop, shadow forth the fierceness of the wrath of God, and the bitterness of his soul under it; whilst cedar's sweet perfume shews how acceptable the smell of the sacrifice was to God; and the ashes referred for common use, intimates his rich salvation, obtained and offered freely to sinners of every class

Numbers 19:11. He that toucheth the dead body of any man— He that touched a dead beast was unclean only one day, Leviticus 11:24; Leviticus 11:47. He that touched the dead body of a man was unclean seven days; so that this was among the greater legal-pollutions; to teach, says Ainsworth, that sin has made mankind the vilest of creatures. The notion of this pollution, which seems to have been almost universal, might probably arise from the natural offensiveness of the object, both to sight and to smell, in hot countries, where dead bodies sooner corrupt. Le Clerc thinks, that the political reason of this law might be, to hinder people from being hardened into cruelty or insensibility, by frequently viewing or touching dead bodies; as also to oblige them to bury their dead as soon as possible, to prevent the inconveniences which might arise from their being unburied in those warm regions; for we may collect from Num 19:15 that they conceive some foul and noxious effluvia to arise from a dead body. Some, however, have conjectured, and with great probability, that the Lord, by Moses, had a higher view in enacting this law; namely, to prevent the Israelites from degenerating into the Egyptian idolatry of worshipping the dead, by preserving their bodies or relics with a superstitious veneration, or performing religious honours at their graves or sepulchral monuments; in opposition to which, Moses ordains, that all persons who did but touch a dead body, or, even the bone of a man, or a grave, Num 19:16 should be unclean seven days.

Numbers 19:12. On the third day, and on the seventh day he shall be clean— See Numbers 19:19. Hence it appears, that this water of separation was designed chiefly for the purging of that great impurity contracted by touching a dead body.—We may also infer from this, that these ashes were kept in all the cities of Judea, where every person might easily have them to put into water, and be sprinkled with it, as they had occasion; for no priest was required to make this purification; but any clean person might sprinkle with it, Numbers 19:18-19.

Numbers 19:14. Dieth in a tent— Wherein they now lived; and, by parity of reason, the same law obliged them, when they came to dwell in houses. All that is in the tent, means all the persons, not all the goods; as appears from the next verse, where only uncovered vessels are declared unclean.

Numbers 19:16. Slain with a sword— In chap. Num 31:19 this is expressed more generally; whosoever hath touched any slain—whether by the sword, or any other instrument.

Numbers 19:19. And on the seventh day he shall purify himself— That is, the person who sprinkled the unclean, as Numbers 19:21.
Such is the law concerning the red heifer, &c. upon which Calmet thus concludes his observations.
We have already remarked, by the way, that the sacrifice of the red heifer was a figure of the passion of Jesus Christ. To be more particular, after Saint Austin and Theodoret: the red heifer, according to them, points out the flesh of Christ, which is taken from an earthly substance. This sacrifice is free from spot and imperfection; to denote the infinite sanctity and innocence of our blessed Lord:—Its sex specifies the infirmity of the flesh wherewith he was clothed. The red colour figures out his passion. The victim was never to have been under the yoke; to signify the liberty with which Jesus Christ suffered humiliations and death, and the power which he possessed of laying down and resuming life when he would. It is Eleazar, not Aaron, who sacrificeth this heifer: which may represent the abrogation of the priesthood in the family of Aaron, to make room for a new and more excellent priesthood. The red heifer is led out of the camp, and wholly consumed by fire: Jesus Christ dies without Jerusalem, Heb 13:11-12 and as there was nothing but purity in his adorable person, he offered it whole and entire to his Father; and the heifer consumed by fire, delineates the resurrection and ascension of the Saviour.