פירוש על פרה 11:6

מטמא את מי חטאת – and even after he ritually immersed, [but] if he didn’t ritually immerse for the purpose of the purification rite it is as if he did not ritually immerse, as is taught in the [second] chapter [of Tractate Hagigah folio 18b/Chapter 2, Mishnah 6]: "אין דורשין"/They do not expound [upon the laws of prohibited relationships]: “[If] he immersed for eating food in the status of Holy Things and is thereby confirmed as suitable for eating food in the status of Holy Things, he is prohibited from engaging in the preparation of purification water.” But once he ritually immersed for the sake of the purification water, even a person who ritually immersed himself that day, according to the Torah, who is invalid for heave-offering and for Holy Things, is fit/appropriate for the purification water, for a person who ritually immersed himself that day/טבול יום is fit for the [ritual of the Red] Heifer.

All that require immersion in water, whether according to the words of the Torah or according to the words of the scribes, defile hatat waters, hatat ashes, and the one who sprinkled the hatat waters, either through contact or through carrying. As we have seen throughout this tractate, the purity regulations for anything that concerns the red cow ritual are more stringent. Therefore, the mishnah teaches that a person who is required to immerse defiles the hatat waters, the hatat ashes or another person who is prepared to sprinkle the waters. This is true whether the person is required by biblical law to immerse or whether he is only required by rabbinic law. Furthermore, he conveys impurity both by contact and by carrying (without contact).

ומזה מי חטאת במגע ובמשא (the one who sprinkles the purification water in contact and carrying) – and in this, everyone does not disagree. But regarding hyssop that is pronounced fit to receive ritual defilement, and because the person who eats them he requires being made fit that [purification] water can come upon him, and similarly, with water that is not mixed [with ashes] and stands for Holy Things, and an empty vessel that is clean and stands in order to place in it the purification ashes, but in this, Rabbi Meir (i.e., contact and carrying) and the Sages (i.e., in contact, but not in carrying) dispute (i.e., if he carried them but did come in contact with them, they are not defiled). And the Halakha is according to the Sages.

And [they defile] hyssop that has been rendered susceptible to uncleanness, and water that had not yet been prepared, and an empty vessel that is clean for the hatat through contact and carrying, the words of Rabbi Meir. But the sages say: only by contact but not by carrying. This section deals with material used in the hatat ritual but that is not the ashes. This includes three items. The first is the hyssop that is used for sprinkling. The hyssop needs to have been rendered susceptible to uncleanness by coming into contact with water (vegetation is never susceptible to impurity until it becomes wet). In this case the water must have been pure for the hatat ritual, otherwise the hyssop would have already been impure. The other two items referred to are water that was drawn to be used for the hatat ritual but has not yet been mixed and the empty vessel. If a person who has to immerse (whether because of biblical or rabbinic law) has contact or even carries one of these things, Rabbi Meir says it is defiled. The other sages rule slightly more leniently. One defiles these things (the hyssop, the unmixed waters and the empty vessel) only if he has direct contact with them. He doesn't defile them through carrying.