4,004. How We Know That Impurity Is Overridden

Hilchos Bias HaMikdash 4:15

Referring to the case in the previous halacha, the reason we look for kohanim from a different family is because the prohibition against serving in a state of ritual uncleanliness is not completely discarded for communal offerings. Rather, the prohibition is still in effect, it is merely overridden out of necessity. This is only done when there’s no other option, which is why we need the tzitz (the plate worn on the Kohein Gadol’s forehead) to atone for impurity, as discussed in halacha 4:7.

Hilchos Bias HaMikdash 4:16

We learn that the prohibition against bringing sacrifices in corpse impurity is overridden in the case of communal offerings from Numbers 9:6, which discusses individuals who were unclean from human remains. Our oral tradition teaches that individuals are pushed off to Pesach Sheni (second Passover) because of corpse impurity but the community is not. If the community at large is unclean with corpse impurity, the general prohibition is overridden and the korban Pesach (Passover sacrifice) is offered in impurity. This is true of every offering that must be brought at a specific time.