A Red Heifer for Purification
Here we have one of the most mysterious sacrifices in the Bible. According to author Grant Jeffrey: "The Talmud claims that the Red Heifer sacrifice was the only one of God's commands that King Solomon, the wisest man who ever lived, claimed he did not understand" (The Signature of God, 1996, pp. 152-153). And indeed, we still may not understand all of the symbolism in this most interesting offering. We do know that we are cleansed by the blood of the supreme sacrifice of Jesus Christ (1 John 1:7). And the book of Hebrews confirms that this is part of the symbolism here: "For if the blood of bulls and goats and the ashes of a heifer, sprinkling the unclean, sanctifies for 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?" (Hebrews 9:13-14). But there is also the fact that the heifer was a representation of Israel in the Scriptures. Perhaps, then, as was mentioned in the discussion on the sin offering, there is some sense of this offering being fulfilled in the people putting to death their old natures. Indeed, that would seem to tie in with having our consciences purged from dead works. Moreover, though there is not sufficient space to elaborate on it here, Christ stood in Israel's place in a number of respects.
In any event, besides the spiritual significance it certainly had, Jeffrey explains that there was a medical benefit to what God was prescribing here as well, just as there was with the laws for dealing with leprosy. In fact, there were clear similarities (compare Leviticus 14:4). Jeffrey states that "the water of purification described in Numbers 19 actually had the ability to destroy germs and infection. The resulting water of purification solution contained ashes from the Red Heifer sacrifice combined with cedar, hyssop and scarlet thread. This water of purification contained 'cedar' oil that came from a kind of juniper tree that grew in both Israel and the Sinai. This cedar oil would irritate the skin, encouraging the person to vigorously rub the solution into their hands. Most importantly, the hyssop tree—associated with mint, possibly marjoram—would produce hyssop oil. This hyssop oil is actually a very effective antiseptic and antibacterial agent. Hyssop oil contains 50 percent carvacrol, which is an antifungal and antibacterial agent still used in medicine, according to the book None of These Diseases. When we note that the waters of purification from the Red Heifer Sacrifice were to be used to cleanse someone who had become defiled and unclean due to touching a dead body, we begin to understand that this law was an incredibly effective medical law as well as a spiritual law" (p. 153).
Of course, it is not clear how much of the cedar and hyssop oil would remain after burning in the fire. There was probably some. But perhaps God was interested more in the symbolism of cleansing agents here than their actual effectiveness. Burning is itself symbolic of purification.
Still, the discussion on open versus sealed containers in the area where someone died should convince any modern reader that God must have had germs in mind to some degree. And it is again worth noting, as in the highlights on leprosy, that there is no way Moses could have understood the need for such advanced medical precautions based on the available knowledge of the time. Divine inspiration is truly the only reasonable conclusion that can be reached.