There is an morbid vaudeville joke about the hapless shlemazel train engineer who was fired from his job.  Feeling depressed, he puts his foot to the third rail, hoping to electrocute himself. Somehow, since this poor guy cannot seem to do anything right, he survives and is not zapped by the high voltage.  Why, you might ask?  Because, of course, he was a poor conductor!

Our Gemara on Amud Beis discusses the concept of “sword is as the corpse”. This is a halakhic principle based on a verse (Bamidbar 19:16) which accords metal utensils which are in contact with a corpse with the same severity of impurity as the corpse.  Various rishonim debate how far this goes, but most hold that this rule is specific to metal.

What is the significance that metal seems to conduct impurity in this manner?  Likkutei Halachos (Hechsher Keylim 1:1-3) explains:

Metal is the source of money and therefore idolatry.  This is why specifically metal utensils must be toiveled and purified if they were originally owned by a gentile. The metal is an attractor and conductor of impurity and must be purged. However, when it comes to spiritual potential, there is always a balance between purity and impurity.  Thus, metal which is particularly receptive to noxious evil forces, also has the ability to ascend and attract higher spiritual forces. This is why in regard to kashrus, a metal utensil absorbs the non-kosher material but can be purged through fire or heat, while earthenware utensils cannot be purged and must be destroyed.

Likkutei Halachos likens the metal utensil to the Jew, who might descend to obscene depths but also can emerge from the furnace of tribulations purged and purified.  We will continue this theme of duality in spiritual potential for purity and impurity on the next daf.