And the Kohen shall wash his clothes and bathe his flesh in water, and afterward he may come into the camp; and the Kohen shall be unclean until evening.
Torah Temimah: Yoma 43a — Why does it say “the Kohen”? — the Kohen in his kehunah.
English: Why does it say “the Kohen”? — the Kohen in his kehunah.
Requirement that the service be performed while the Kohen is in a state of active kehunah.
The washing of the clothes and the immersion after involvement with the para must be done by a Kohen who is functioning in his priestly status.