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". 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. 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).