Numbers 19:10

And he that gathereth the ashes of the heifer shall wash his
clothes
Whom the Targum of Jonathan calls a priest, though it does not seem necessary he should be one:

and be unclean until the even; (See Gill on Numbers 19:7);

and it shall be unto the children of Israel, and unto the stranger
that sojourneth among them, for a statute for ever;
until the Messiah came, whose sufferings and death are for the expiation of, and purification for the sins of Jews and Gentiles, of all the people of God throughout the world, signified by the burning of this heifer; see ( 1 John 2:2 ) .