Halakhah sobre Números 19:15

With regard to the defilement engendered by a corpse, Numbers 19:14 specifies that "… every [person] who comes into the tent shall be unclean seven days." The immediately following verse, Numbers 19:15, spells out the circumstances in which vessels and utensils are defiled: "And every open vessel which has no covering close-bound upon it is unclean." The clear inference is that the converse, i.e., a closed vessel that is tightly sealed, does not become defiled. The Mishnah, Kelim 10:1, declares that not only is such a utensil not subject to defilement but the utensil also preserves anything that may be contained within its walls from becoming defiled. Rabbinic tradition teaches that biblical law limits the capacity of a sealed utensil to preserve its contents from defilement to vessels such as pottery and earthenware that are not subject to defilement by tactile contact with the exterior of the vessel.