Numbers 19:21

ומזה מי הנדה AND HE THAT SPRINKLED THE WATER OF SPRINKLING [SHALL WASH HIS GARMENTS] — Our Rabbis said that the one who sprinkles remains clean, and this statement is intended to intimate that one who bears the waters of purification becomes unclean with a more stringent uncleanness, in that he renders unclean the garments that are upon him (for it states here that he shall wash his garments), which is not so in the case of one who only touches these waters. And this fact that it here expresses it (the idea of “bearing the waters”) by the term “he that sprinkles” is only to tell you that they (the waters) do not render a person who bears them unclean unless they contain a quantity capable of being sprinkled (Yoma 14a). והנגע…יטמא AND HE THAT TOUCHETH … SHALL BE UNCLEAN, but does not require washing of his garments.

וְהָיְתָ֥ה לָהֶ֖ם לְחֻקַּ֣ת עוֹלָ֑ם וּמַזֵּ֤ה מֵֽי־הַנִּדָּה֙ יְכַבֵּ֣ס בְּגָדָ֔יו וְהַנֹּגֵ֙עַ֙ בְּמֵ֣י הַנִּדָּ֔ה יִטְמָ֖א עַד־הָעָֽרֶב׃

And it shall be a perpetual statute to them, that he that sprinkles the water of sprinkling shall wash his clothes; and he that touches the water of sprinkling shall be unclean until the evening.