Talmud do Liczb 19:15

There are Tannaim who state “impurity of the dead”. There are Tannaim who state “by the impurity of the dead”¹⁹⁷This is about the wording of R. Aqiba’s statement. A dead human body is the source of original impurity. A person or vessel touching the dead becomes originally impure, carrying “the impurity of the dead”.
A vessel touching such a person or vessel becomes impure in the first derivative degree “by the impurity of the dead”.. He who said “impurity of the dead”, about vessels that have to be rinsed¹⁹⁸Impure clay vessels cannot be purified, but become pure only as potsherds or otherwise impossible to use as containers. The expression “vessels to be rinsed” comes from Lev. 6:21 where it characterized metal pots. In rabbinic usage, the expression is applied to all vessels that can be purified; here it applies to wooden vessels since metal vessels are excluded in the next sentence.
The separate treatment of metal in cases of impurity of the dead is based on Num. 19:16 where in the expression “slain by the sword” the mention of “sword” seems to be superfluous in the context and therefore one concludes that the sword, and by extension any metal, acquires the super-impurity of the dead to impart original impurity to its contents and anything it comes in contact with (Sifry Num. 127). The contents of the wooden vessel are impure in the second degree but those in the metal vessel in the first.. He who said “by the impurity of the dead”, about metal vessels. What is the reason? Any open vessel etc. is impure¹⁹⁹Num. 19:15, referring mainly to clay vessels but also to all other non-metallic containers (Sifry Num. 126).. [It is] impure but does not become a source of impurity to transmit impurity.¹⁹⁵As explained in Sotah 5:2, R. Aqiba takes טמא as a transitive verb. Therefore he reads the expression יטמא as “will transmit impurity”, in contrast to טָמֵא “is passively impure.” This applies not only to Num.19:22 but also to Lev. 11:32–35.