Then the priest must wash his clothes and bathe his body in water; after that he may enter the camp, but he will be ceremonially unclean until evening.
7 Then the priest shall wash his clothes. At first sight there seems to be a discrepancy in the facts, that the heifer was sacred to God, and pure, and still that the priest was polluted by touching it; yet they accord very well with each other.
We have here the divine appointment concerning the solemn burning of a red heifer to ashes, and the preserving of the ashes, that of them might be made, not a beautifying, but a purifying, water, for that was the utmost the law reached to; it offered not to adorn as the gospel does, but to cleanse only.
Commenting on Numbers 19:1-10
Then the priest shall wash his clothes,.... The Targum of Jonathan has it,"he that slew the cow,''and Aben Ezra, the priest that burnt it; but it seems to mean Eleazar, the priest that sprinkled the blood, and by touching that was defiled and needed washing; and so the Jews (l) say, all that were employed about it, from the beginning to the end, were defiled...