Parah, Chapter 11, Mishnah 6. This chapter deals with the purity required around the waters of the parah adumah, the mei chatas, and with the status of people who are obligated to immerse in a mikveh. Our mishnah teaches how strict the standards of the chatas are: even a person whose obligation to immerse is only rabbinic can spoil the chatas waters and its ashes.
The Mishnah lays down a broad rule: "Kol hataun bias mayim", every person upon whom an obligation to enter the water of a mikveh rests. This holds true whether that obligation is "midivrei Torah", imposed by Torah law, or "midivrei sofrim", instituted by the Sages. Such a person is "metamei es mei chatas", he conveys impurity to the waters of the chatas; "ve'es eifer chatas", and to the ashes of the parah adumah; "ve'es hamazeh mei chatas", and even to the man who performs the sprinkling. All of this applies "bemaga uv'masa", through contact and through carrying alike.
Two entries in this list need a word of explanation. When the ashes are mentioned, the reference is to them in their unmixed state, before any water has been added. And as for the mazeh, the Gra understands the term to include anyone whose purity currently qualifies him to perform the sprinkling; once our man makes contact with him, that qualification is gone. Regarding contact and carrying: it makes no difference whether he laid a hand directly on these items or bore the vessel in which they were held. Either way impurity results.
Here a striking contrast is worth noting. If a man immersed for the sake of the chatas and the sun has not yet set, so that he is a tevul yom from an impurity of Torah law, he remains unfit for terumah and for kodesh until nightfall. Nevertheless he is considered pure with respect to the chatas, for a tevul yom is pure for the service of the parah adumah. The standards of the chatas are stricter in some respects and more lenient in others.
A second list follows, with a narrower rule. "Ha'ezov hamuchshar", hyssop that has already become susceptible to impurity; "vehamayim she'einan mekudashim", water in which the ashes have not yet been mixed; "uchli reikam hatahor lechatas", a vessel standing empty whose purity has been guarded for chatas use. Concerning all three, our man conveys impurity "bemaga uv'masa", whether he handles them or carries them. So rules Rebbi Meir.
The Sages, however, take a different view. "Vachachamim omrim": their ruling is "bemaga aval lo bemasa", his handling of these three items conveys impurity to them, but his carrying of them does not.
What exactly is meant by "carrying" here? The Mishnah Achronah explains that the Mishnah is not speaking of literally lifting the items, but of heses, causing them to move. If a person in this state sets the water or the ashes in motion, that movement is heses, and it is heses that Rebbi Meir holds transmits impurity to these items. The Chachamim disagree, and the halachah follows the Chachamim: heses, or carrying, does not render these things impure. Only direct contact does.
The mishnah therefore leaves us with a clear picture. Where the chatas waters and ashes themselves are concerned, even a lightly impure person spoils them by touch or by carrying. But regarding the hyssop, the unsanctified water and the empty vessel designated for the chatas, only his touch is a problem, and not the movement he causes.