Many commentators suggest this chapter is dealing with the events after the plague mentioned in Numbers 16:46-50. After the plague there were many dead bodies around and so, Israel now needs to become physically and spiritually clean, Leviticus 12-15.
God tells Moses and Aaron that this is a requirement of the law that He has commanded, they are to tell the Israelites to bring them a red heifer without defect or blemish, Leviticus 4:3, and that has never been under a yoke, Numbers 19:1-2.
Coffman, in his commentary, says the following.
‘The animal is certainly not called a red cow in the New Testament, and despite the fact that the word ‘cow’ can occasionally mean an older animal, even one with a calf, 1 Samuel 6:7.’
Keil, in his commentary, says the following.
‘The word for heifer here does not generally mean cow, but a young cow, a heifer, Hebrews 9:13.’
The red heifer was to be presented to Eleazar and was to be slain outside the camp, Numbers 19:3 / Exodus 29:14 / Leviticus 4:3 / Leviticus 4:11-12 / Leviticus 4:21 / Hebrews 9:13-14 / Hebrews 13:11-12. Eleazar is to take some of its blood on his finger and sprinkle it seven times toward the front of the tent of meeting, Numbers 19:4. While he watches, the heifer is to be burned, its hide, flesh, blood and intestines, Numbers 19:5.
Constable, in his commentary, says the following.
‘The Israelites were to slay the animal outside the camp because of its connection with sin and death. The high priest was to observe the slaying making sure the person in charge did it properly. This was a very important sacrifice. The sprinkling of the blood shows that this slaying was a sin offering. The animal died for the sin of the congregation, Numbers 19:4.
Clarke, in his commentary, says the following.
1. The red heifer with them signifies the flesh of our Lord, formed out of an earthly substance.
2. Being without spot, the infinite holiness of Christ.
3. The sex of the animal, the infirmity of our flesh, with which he clothed himself.
4. The red colour, his passion.
5. Being unyoked, his being righteous in all his conduct, and never under the yoke of sin.
6. Eleazar’s sacrificing the heifer instead of Aaron, Numbers 19:3, signifies the change of the priesthood from the family of Aaron, in order that a new and more perfect priesthood might take place.
7. The red heifer being taken without the camp, Numbers 19:3, to be slain, points out the crucifixion of our Lord without the city.
8. The complete consuming of the heifer by fire, the complete offering of the whole body and soul of Christ as a sacrifice to God for the sin of man: for as the heifer was without blemish, the whole might be offered to God and as Christ was immaculate, his whole body and soul were made a sacrifice for sin.
9. As the fire of this sacrifice ascended up to God, so it points out the resurrection and ascension of our blessed Lord.
10. And as the ashes of this victim communicated a legal purity to those who were defiled, so true repentance, signified by those ashes, is necessary for the expiation of the offences committed after baptism. A great part of this is true in itself but how little evidence is there that all these things were intended in the ordinance of the red heifer? Numbers 8:7.
Notice when the heifer was burnt, the priest would also put cedarwood and hyssop, Numbers 19:6 / Leviticus 14:4 / Psalm 51:7 / Matthew 27:48, and scarlet wool, Exodus 26:31 / Exodus 28:5-6 / Numbers 4:8 / Joshua 2:21 / Matthew 27:28, into the fire. Each of these three items are used in the cleansing ceremony for a leper, Leviticus 14:4-6. Each of these items has a special significance.
After that, the priest must wash his clothes and bathe himself with water, Numbers 19:7. This water was used for the ceremonial cleansing of those who were impure from the defilement of sin, Numbers 8:7.
The priest may then come into the camp, but he will be ceremonially unclean till evening, Numbers 19:7. The man who burns it must also wash his clothes and bathe with water, and he too will be unclean till evening, Numbers 19:8. A man who is clean shall gather up the ashes of the heifer and put them in a ceremonially clean place outside the camp, Numbers 19:9.
Barnes, in his commentary, says the following.
‘The ashes were to be kept, in order to be mixed with water, Numbers 19:17, and sprinkled on those who had contracted any legal defilement.’
Coffman, in his commentary, says the following.
‘There was indeed a genuine and pertinent symbolism in this ceremony is certain in the light of Hebrews 9:13 / Hebrews 13:11. In that New Testament passage, the sprinkling of the ashes of the heifer is ranked with all the other sacrifices as typical of the blood of Christ, the detail of the heifer’s being burnt ‘without (outside) the camp’ being applied specifically as a prophecy of Christ’s suffering ‘without the camp’.’
Note that the KJV uses the words, ‘water of separation,’ in Numbers 19:9.
Barnes, in his commentary, says the following.
‘In Numbers 8:7, the water of purification from sin is the ‘water of purifying.’ So that which was to remedy a state of legal separation is here called ‘water of separation.’
The ashes were then mixed with the water of separation that was used for the removal of sin, Numbers 19:9. The man who gathers up the ashes of the heifer must also wash his clothes, and he too will be unclean till evening, Numbers 19:10. This will be a lasting ordinance both for the Israelites and for the foreigners residing among them, Numbers 19:10.
If this chapter is dealing with the previous plague, where there were many dead bodies around, Numbers 16:46-50, then many of the Israelites would have come into contact with a dead body.
Whoever touches a human corpse will be unclean for seven days and they must purify themselves with the water on the third day and on the seventh day and then they will be clean, Numbers 19:11-12 / Leviticus 11:24 / Leviticus 11:27 / Leviticus 11:39. However, if they do not purify themselves on the third and seventh days, they will not be clean, Numbers 19:12.
If they fail to purify themselves after touching a human corpse, they defile the LORD’s tabernacle and they must be cut off from Israel because the water of cleansing has not been sprinkled on them, they are unclean and their uncleanness remains on them, Numbers 19:13.
This is the law that applies when a person dies in a tent if anyone who enters the tent and anyone who is in it will be unclean for seven days, and every open container without a lid fastened on it will be unclean, Numbers 19:14-15. If anyone out in the open touches someone who has been killed with a sword or someone who has died a natural death, or anyone who touches a human bone or a grave, will be unclean for seven days, Numbers 19:16.
Although it was possible to become unclean through other means, Numbers 19:14-16, the emphasis here appears to be on those who had come into contact with a dead body, one of those who had died during the plague. Remember, anyone who touched an unclean animal was classed as unclean, but only until evening, Leviticus 11:24-29, here however, the uncleanness from touching the corpse of a human being lasted seven days, Numbers 19:14 / Numbers 19:16.
Constable, in his commentary, says the following.
‘God recognized that the incubation period for most bacteria is within seven days. This means that after exposure to a disease, a person will know within seven days whether the disease is contracted.’
For the unclean person, put some ashes from the burned purification offering into a jar and pour fresh water over them, Numbers 19:17. Then a man who is ceremonially clean is to take some hyssop, dip it in the water and sprinkle the tent and all the furnishings and the people who were there, Numbers 19:18. He must also sprinkle anyone who has touched a human bone or a grave or anyone who has been killed or anyone who has died a natural death, Numbers 19:18.
The man who is clean is to sprinkle those who are unclean on the third and seventh days, and on the seventh day he is to purify them, Numbers 19:19. Those who are being cleansed must wash their clothes and bathe with water, and that evening they will be clean, Numbers 19:19.
However, if those who are unclean do not purify themselves, they must be cut off from the community, because they have defiled the sanctuary of the LORD, Numbers 19:20. The water of cleansing has not been sprinkled on them, and they are unclean, Numbers 19:20.
This is a lasting ordinance for Israel, the man who sprinkles the water of cleansing must also wash his clothes, and anyone who touches the water of cleansing will be unclean till evening, Numbers 19:21. Anything that an unclean person touches becomes unclean, and anyone who touches it becomes unclean till evening, Numbers 19:21.
This wasn’t just about being physically cleansed but spiritually cleansed, Deuteronomy 6:4-5 / Deuteronomy 30:6 / Ezekiel 36:25-38 / 1 Corinthians 6:19-20. And we must note that the priests were not even necessary in the cleansing ceremonies connected with the whole house, Matthew 23:7.
All this cleansing was very important for Israel to remain right with God, however, all the sacrifices and cleansing were a foreshadow of what was to come and be fulfilled in Christ, Hebrews 9:13-14 / 1 John 1:7-9.
Jamieson, in his commentary, says the following.
‘It taught that the purifying efficacy was not inherent in the ceremony itself, but arose from the Divine appointment, as in other ordinances of religion, which are effective means of salvation, not from any virtue in them, but solely from the grace of God.’