Purity Laws

The nativity stories in Matthew and Luke are deeply rooted in Jewish Scripture and Second Temple Judaism. Nevertheless, over the centuries they have accumulated interpretations that portray Jews as cruel, greedy, impure, or spiritually blind. A closer look at familiar claims—from Mary’s supposed threat of being stoned to the caricature of shepherds as social outcasts—shows how antisemitism often enters the Christmas story not through the Gospels themselves, but through their interpretation.

In Priestly law, impurity is stripped of its mythic origins in the demonic realm but still retains its dangerous, physical presence, and must be mitigated by specific acts of ritual cleansing and banishing, depending on the type of impurity. Purification from the skin disease tzaraʿat (Leviticus 13–14) offers the starkest example of such a ritual.

Deuteronomy and Leviticus drew on common Vorlage (source text) to develop their regulations about the consumption of land, marine, and winged creatures. While Deuteronomy only lightly modifies this Vorlage, the editors of Leviticus expanded the text in several stages to align it with Priestly ideology.

Several stories describe how the rabbis of the Second Temple period would force priests to prepare the ashes in the lower state of purity, tevul yom (immersed in water before sunset), and once even discarded ashes prepared in the stringent state of purity, meʿorav shemesh (after sunset), to demonstrate the law is not in accordance with the Sadducees. The Qumran halakhic text, 4QMMT, gives us the perspective of the other side of the debate.

Hint: The story follows the red heifer ritual, i.e., the laws of corpse contamination, and the death of their sister Miriam.

After contact with a corpse, a person must be sprinkled with a liquid mixture containing the ashes of a red heifer, together with cedar and ezov, alkaline plants that, when burnt, function as the key ingredients in a detergent.

Why is partially infected skin impure but fully infected skin pure? Mary Douglas’ insight into the polluting power of anomalies helps us make sense of this counterintuitive rule.

Three curious details in the plagues of blood and frogs show the hand of a post-priestly editor and his concern about purity laws.

After giving birth to a male, the mother is impure for 7 days, followed by 33 days of purification. However, with a female, the mother is impure for 14 days, followed by 66 days of purification.

Mesopotamian gynecological texts and what we know about women’s postpartum flow help us parse the unusual Hebrew idiom demei tohorah, literally “bloods of purity” (Leviticus 12), to describe the second stage of postpartum bleeding.

The root ק.נ.א “jealous zeal” in the chapter on the sotah (Numbers 5) highlights a key goal of the ritual and its accompanying offering, namely, to remove the husband’s jealous zeal and allow him to remain with his wife without guilt.

Already in the early 2nd millennium B.C.E., people knew that diseases were contagious, and fear of contagion plays a key role in the Torah’s laws regarding the skin ailment, tzaraʿat. What does this mean for understanding other kinds of tum’ah?

A child’s mother remains impure for forty days after the birth of a boy and eighty days after a girl. A comparison of this procedure with similar ones in Hittite birth rituals suggests that this gender-based differentiation serves as a kind of ritual announcement of the child’s gender.

In Leviticus 15, the laws of niddah are about purity; Lev 18 and 20, however, prohibit sex during menstruation. The rabbis, who inherited both of these texts, create a new, hybrid concept: the prohibition of sex while a woman has the status of menstrual impurity.

Leviticus 15 describes two types of impure bleeding for women: menstruation (niddah), and bleeding that is “not during her menstrual period (zavah).” The Rabbis attempt to define the difference in an abstract manner, and in so doing, elide the two.

Why can’t a man remarry his wife once she has been married to someone else?

Moses tells the soldiers returning from the Midianite war that they must purify themselves from corpse impurity. Elazar then jumps in with a unique law in Moses’ name about the need to purify metal in fire. Critical and traditional scholars alike—including the scribes of the Samaritan Pentateuch—were troubled by why Elazar and not Moses teaches this law.

Leviticus 21 and Ezekiel 44 regulate whom priests may marry. What rationale lies behind these laws?

In reference to the parturient, the Torah speaks of a 33 or 66 day period of דמי טהרה “blood of her purity” as distinguished from a 7 or 14 day period “like menstruation.” What is the difference between these two periods according to Leviticus and how did later groups such as rabbinic Jews, Karaites, Samaritans, and Beta Israel understand it?

Despite its lengthy coverage of tzaraat, biblical “leprosy,” the Torah omits discussion of its cause, its infectiousness, and its treatment. Comparison to the Mesopotamian rituals pertaining to a strikingly similar disease, Saḫaršubbû, shows that these omissions were far from accidental.

When and why washing became immersion: between traditional-rabbinic and scientific-critical approaches to the origin of immersion and the mikveh.

Ezekiel 36 uses Priestly “purification” imagery similar to that of the red heifer ritual to describe God’s future reconciliation with Israel, inspiring the rabbis to choose this passage as the haftara for Parashat Parah.

Leviticus 15:24 does not declare sex with a menstruating woman to be forbidden, only that it results in temporary impurity. Leviticus 18:19 and 20:18, however, strictly prohibit it. What accounts for these two different approaches?

Is the purification ritual or spiritual?

Deuteronomy requires Israelite soldiers to carry a shovel with them for covering their feces, outside the war camp, because God is in the camp. The Qumranites and Karaites assume that feces must be impure, while the rabbis extend the law to include times of prayer and Torah study, and maintaining human decency at all times.

The dietary laws in Leviticus are not expressed in terms of kosher (כשר) or not kosher but in the terms of the Priestly purity laws: purity (טהרה), pollution (טומאה), and disgust (שקץ).

Immersing in the Priestly Text: In support of Dr. Rabbi Zev Farber's contention in “The Purification of a Niddah: The Torah Requirement” that the Torah does not require women to immerse after niddah in order to become pure.

A rejoinder to Rabbi Dr. Zev Farber’s “The Purification of a Niddah: The Torah Requirement.”

Jewish law requires a menstruant woman to purify herself by immersing in water. A schematic look at Leviticus 15 actually implies this is not a Torah requirement.

The Archaeological and Textual Evidence