According to Numbers 19:2: “Speak unto the children of Israel, that they bring thee a red heifer without spot, wherein is no blemish, and upon which never came yoke”. 1
The Book of Numbers stipulates that the animal must not have hairs of any other color, must be in perfect health, and it must not have been used to perform work (Numbers 19:2). The heifer is then ritually slaughtered (Numbers 19:3) and burned outside of the camp (Numbers 19:3–6). Cedar wood, hyssop, and scarlet are added to the fire, and the remaining ashes are placed in a vessel containing pure water (Numbers 19:9).
In order to purify a person who has become ritually contaminated by contact with a corpse, water from the vessel is sprinkled on him, using a bunch of hyssop, on the third and seventh day of the purification process (Numbers 19:18–19).
The priest who performs the ritual then becomes ritually unclean, and must then bathe himself and his clothes in a ritual bath. He was be deemed impure until evening.
The Mishnah, the central compilation of Rabbinic Oral Law, contains a tractate on the Red Heifer, Tractate Parah (“Cow”) in Seder Taharot, which explains the procedures involved. The tractate has no existing Gemara, although commentary on key elements of the procedure is found in the Gemara for other tractates of the Talmud.
The animal must be entirely of one color, and there are a series of tests listed by the rabbis to ensure this, for instance, the hair of the cow must be absolutely straight (to ensure that the cow had not previously been yoked, as this is a disqualifier). According to Mishnah Parah, the presence of two black hairs invalidates a Red Heifer. In addition to the usual requirements of an unblemished animal for sacrifice.
According to Jewish tradition, only nine Red Heifers were actually slaughtered in the period extending from Moses to the destruction of the Second Temple. Mishnah Parah recounts eight, stating that Moses prepared the first, Ezra the second, Simon the Just and Yohanan the High Priest prepared two each, and Elioenai ben HaQayaph and Hanameel the Egyptian prepared one each (Mishnah Parah 3:5).
The absolute rarity of the animal, combined with the detailed ritual in which it is used, have given the Red Heifer special status in Jewish tradition. It is cited as the prime example of a khok, or biblical law for which there is no apparent logic, and is therefore of absolute Divine origin.
Because the state of ritual purity obtained through the ashes of a Red Heifer is a necessary prerequisite for participating in Temple service, efforts have been made in modern times by Jews wishing for biblical ritual purity and in anticipation of the building of The Third Temple to locate a red heifer and recreate the ritual. However, multiple candidates have been disqualified, as late as 2002.
When a person became ceremonially unclean by some contact with an unclean animal or person or by contact with a dead person, he was required to go through a ritual cleansing. The material for this purification was composed of running water and the ashes of the “red heifer” (Num. 19).
The ashes were prepared as follows:
A heifer, without blemish, and which had never been yoked, was slaughtered outside the camp.
The son and successor of the high priest dipped his finger in the blood and sprinkled it seven times toward the sanctuary.
The heifer was burned in the presence of the priest, who, at the same time, took the cedar wood, hyssop, and scarlet wood, and cast them into the flames.
A man who was free from defilement gathered the ashes and carried them to a clean place, still outside the camp, where they were stored for use as needed. All persons who were involved with this ceremony were considered unclean until that evening.
When someone needed to have the purification rite performed on him, a man, who was himself free from defilement, took some of the ashes, put them in a vessel, and poured some fresh running water over them.
He dipped a bunch of hyssop into the mixture and sprinkled it upon the person to be purified, once three days after the uncleanness had been contracted, and again seven days after.
At the same time, the tent in which a corpse had lain and all the furniture were sprinkled with the same water.
The red heifer offering is called a sin offering (Num. 19:9,17), and it portrays the sacrifice of Christ as the medium of the believer’s cleansing from the pollution contracted by his contact with the world. The order of cleansing is:
The slaying of the sacrifice
The sevenfold sprinkling of the blood, showing the completed putting away of the believers sins before God (Heb. 9:12–14).
The burning of the sacrifice to ashes and their preservation as a memorial of the sacrifice
The cleansing by sprinkling with ashes mixed with water, typical of the Holy Spirit and the Word of God (John 7:37–39; Eph. 5:26).
The whole ritual shows the fact that the Holy Spirit used the Word of God to convict the believer of sin, thus making the believer conscious that the guilt of sin was to be borne by Christ in His sacrifice. Instead of losing hope, the convicted believer confesses the unworthy act and is forgiven and cleansed (John 13:3–10; 1 John 1:7–10).
This introduction is from the Wikipedia article “Red Heifer”.↩