Evidence for Intrinsic or Derived Gentile Ritual Impurity:
Several texts have been taken as evidence for the claim that Gentiles are deemed to bear an intrinsic impurity equivalent to corpse impurity or to be defiled by corpse impurity, yet these texts are for the most part ambiguous and inconclusive. The ambiguity arises in some cases from the rabbinic decree that a Gentile, though not impure by Torah law, should be considered to defile like a zav (see discussion pages 122–131). 1 Sometimes a Gentile is described as defiling objects in a manner consistent with the defilement generated by both a zav and a corpse contaminant. In such cases, it may be impossible to determine if the Gentile's ability to defile derives from his statutory status as a zav (by rabbinic decree) or because he is believed to suffer from corpse impurity or some other factor (e.g., his profane status). At the very least, it may be said that corpse defilement is never an inescapable conclusion.
Among the sources identified by Alon (1977:149–156) as exemplifying a law of Gentile defilement in early times is t. AZ 8 (9):2, which requires the immersion of vessels — even unused vessels — purchased from Gentiles. Alon dismisses what he believes to be a later amoraic explanation of this law 2 and argues that according to the plain sense of the text, the ritual immersion of these vessels is not different from all other immersions: The immersion is purificatory and is intended to purify the vessel from Gentile uncleanness. 3 However, a close examination of the relevant sources suggests otherwise. Tannaitic rules for the immersion of vessels obtained from Gentiles are based on a paradigm case in Scripture in which vessels are acquired (as a result of a military defeat) from Gentiles. Numbers 31:22–23 details the two procedures to be followed to cleanse the vessels taken as war booty from the Midianites:
22. Gold and silver, copper, iron, tin, and lead
23. — any article that can withstand fire — these you shall pass through fire and they shall be clean (except that they must be cleansed with water of lustration); and anything that cannot withstand fire you must pass through water.