Tumah and taharah
In Jewish law, ṭumah (, ) and ṭaharah (, ) are the state of being ritually "impure" and "pure", respectively. The Hebrew noun "ṭum'ah", meaning "impurity", describes a state of ritual impurity. A person or object which contracts "ṭumah" is said to be "ṭamé" ( Hebrew adjective, "ritually impure"), and thereby unsuited for certain holy activities and uses ("kedushah", in Hebrew) until undergoing predefined purification actions that usually include the elapse of a specified time-period. The contrasting Hebrew noun "ṭaharah" () describes a state of ritual purity that qualifies the "ṭahor" (; ritually pure person or object) to be used for "kedushah". The  most common method of achieving "ṭaharah" is by the person or object being immersed in a "mikveh" (ritual bath). This concept is connected with ritual washing in Judaism, and both ritually impure and ritually pure states have parallels in ritual purification in other world religions. The laws of "ṭumah" and "ṭaharah" were generally followed by the Israelites, particularly during the First and Second Temple Period, and to a limited extent are a part of applicable "halakha" in modern times. Etymology. The Hebrew noun "ṭum'ah" () derives from the verb "ṭamé" (), in the qal form of the verb "to become impure"; in  the niphal to "defile oneself"; and in the transitive Piel to defile something or pronounce something impure. The verb stem has a corresponding adjective, "ṭamé" (טָמֵא), "impure". Likewise the Hebrew noun "ṭahara" () is also derived from a verb, in this case "ṭaher" () "to be ritually pure". and in the transitive piel "to purify". The verb and noun have a corresponding adjective, "ṭahor" (), "ritually pure". The word is a cognate to the Arabic word 'طهارة' "ṭahāra(h)" (pronounced almost identically, with the elongation of the second 'a') which has the same meaning in Islam. Some sources, such as Samson Raphael Hirsch on  Genesis 7:2, claim that the meaning is "entombed", meaning the person or item that is in the "tame" state is blocked, and not in a state of receiving holy transmission. "Ṭahor", by contrast, is defined as "pure" in the sense that the person or object is in a clear state and can/may potentially serve as a conduit for Divine and Godly manifestation. Although "ṭumah and ṭaharah" is sometimes translated as "unclean and clean", it is more a spiritual state than a physical one. Once initiated (for the physical signs that initiate tzaraath, zav and niddah, see below) it is  generally immeasurable and unquantifiable by known mechanical detection methods, there is no measure of filth, unsanitary, or odorous affiliation with the state of "ṭumah", nor any mechanically measurable level of cleanliness, clarity, or physical purity for the state of "ṭaharah". In the Bible. Usage. The noun form of "ṭumah" is used around 40 times in the Masoretic Text of the Hebrew Bible is generally translated as "uncleanness" in English language Bibles such as the KJV, and JPS Tanakh. The majority of uses are in Leviticus. Though uses for national impurity occur in Ezra and Ezekiel, and Zechariah prophesies the removal  of the "prophets and spirit of impurity () from the land". The adjective "tamei" () "impure", is much more common. The verb form of "ṭaharah" (), the verb "ṭaher" () "be pure", is used first in the Hebrew Bible is in , where Jacob tells his family to "put away strange gods, and be pure". In general, the term "tumah" is used in two distinct ways in the Hebrew Bible: In general, "tumah" in the sense of "ritual impurity" is prefixed by the letter lamed or lacks any prefix at all, while "tumah" in the sense of "moral impurity" is prefixed by the letter bet . Ritual impurity. Activities which create impurity. The Torah, particularly the book of Leviticus, lists various activities which create an "impure" ("tamei") status: Some of these activities are forbidden (i.e. eating non-kosher meat), others are permitted (i.e. sex between a married couple), and others are unavoidable (i.e. if a person dies suddenly while other people are in the house). Thus, there is no automatic moral stigma to becoming "impure". Implications of impure status. Certain activities are prohibited as a result of acquiring this "impure" status. For example: Just as it is a severe offense to bring impurity into the Israelite  sanctuary, "impurity" is also seen as a means of nullifying a worship site of other religions; though the rules for this impurity are not made clear. Becoming pure again. Different forms of impurity requires various rituals in order to regain a "pure" ("tahor") status. For example: Moral impurity. The term "tumah" is also used to refer to certain sins, for which there is no specific ritual to remove the impure status. For example: In a number of cases, no specific sin is mentioned; overall sinful behavior has led to impurity. In Ezra–Nehemiah. Christine Hayes argues that moral impurity is  the reason for the gentile expulsion and alienation that occurs in Ezra–Nehemiah. However, S.M. Olyan argues that Ezra and Nehemiah's attempt of the restoration of Israel to its original state was expressed through the expulsion and alienation of foreign peoples that was caused by both ritual and moral impurities. The Judean people believed that Israel and the priestly bloodline of Israel in itself was pure, being the chosen nation of their God. Furthermore, when the men of Israel committed to relations with Gentile people the acts took away from their purity. Olyan argues that there were different actions  that were categorized by the Judean people as ritual impurity and moral impurity. Moral impurity can simply be removed, as in physical removal or separation between groups; thus expulsion of the Gentiles from the Judean environment was enough to re-purify the environment. However, ritual impurity is much more serious. Olyan argues that ritual impurity is deeply embedded into covenants, thus a religious ritual must be performed to rid the impurity from the people group. In rabbinic literature. The Mishnah devotes one of its six sub-divisions, named Tohorot ("purities"), to the laws of ritual impurity. Neither the Babylonian nor  the Jerusalem Talmud contains systematic commentaries to the tractates of Tohorot (except for Niddah), as these laws had little practical relevance after the destruction of the Temple. However, the laws are discussed many times in other tractates, and in later rabbinic literature. Maimonides clarifies that, in addition to all of Israel, the priests are expected to be knowledgeable and fluent in the general and specifics of "ṭumah and ṭaharah" law. Given his role of Temple service and year round consumption of "terumah", each priest was required to be in a "ṭahor" state. Mandatory or optional. The mainstream view among rishonim  and non-Kabbalistic authorities is that one is permitted to become "tamei" (except on those occasions when one must visit the Temple, or touch holy objects), and thus there is no obligation to attempt to remain "tahor". As an example, it is not only permitted but a mitzvah to tend to a dead person, even though this causes impurity. However, some rabbis have advocated keeping some of the laws of purity even in the absence of the temple in Jerusalem and even in the diaspora. One category that was commonly kept in Talmudic and pre-Talmudic times is "ṭumath ochlin  v'mashkin" (consuming food and drink that did not become "ṭamei"). Sages such as Rabban Gamaliel and Hiyya the Great encouraged eating only pure food at all times. Targum Yonathan considered this to be implicit in . One who kept this stringency was called a "porush", meaning "separated" (from "ṭumah"). This was also one of the criteria for being a "haver" (a "friend" or "fellow" with whom the rabbis could eat without risk of violating purity laws), and according to some, the main criterion. Additionally, some rabbis advocated abstaining from the "midras" of a "niddah". Rabbi Menachem Schneerson discouraged abstaining from any  object made impure by a menstruating woman in modern times, with the exception for unique individuals. Hierarchy of impurity. The rabbis describe a hierarchy of levels of impurity. In general, each level can result from touch by the level above it. The levels are: Impurity of scrolls. The rabbis declared Torah scrolls to be impure by rabbinic law. This seemingly strange law had a practical purpose: it discouraged Jews from storing their terumah produce alongside Torah scrolls, which attracted mice and caused the Torah scrolls to be nibbled on as well. In modern times. Following the destruction of the Second  Temple, ritual impurity status ceased to have practical consequences, with the exception of "niddah" and "zav/zavah". These rules are still practiced in Orthodox Judaism. In Conservative Judaism, while the concept of "niddah" and a prohibition on sexual relations during the "niddah" period (including childbirth) are still agreed upon, recent decisions by the Committee on Jewish Law and Standards have endorsed multiple views about the concept of "zavah", as well as the "tumah" status of a "niddah". The liberal view held that the concepts of "ṭumah" and "ṭaharah" are not relevant outside the context of a Holy Temple (as distinct  from a synagogue; hence a "niddah" cannot convey "ṭumah" today), found the concept of "zavah" no longer applicable, and permitted spouses to touch each other in a manner similar to siblings during the "niddah" period (while retaining a prohibition on sexual conduct). The traditional view retained the applicability of the concepts of "tumah", "ṭaharah", and "zavah", and retained a prohibition on all contact.