The clean person shall sprinkle upon the unclean person... and he shall be clean at evening... [But] he that sprinkles the water of sprinkling... shall be unclean (19:19-21)
All who are involved in the preparation of the Heifer from beginning to the end, become impure, but the Heifer itself purifies the impure! But G‑d says: I have made a chok, decreed a decree, and you may not transgress My decrees.
(Midrash Tanchuma)
The fact that the ashes of the Heifer "purify the contaminated and contaminate the pure" carries an important lesson to us in our daily lives: If your fellow has been infected by impurity and corruption, do not hesitate to get involved and do everything within your power to rehabilitate him. If you are concerned that you may became tainted by your contact with him, remember that the Torah commands the Kohen to purify his fellow Jew, even though his own level of purity will be diminished in the process.
(The Lubavitcher Rebbe)
