R’ Chaim Vital once asked the Arizal if it was permitted to use the Holy Names of Hashem (Sheimos Hakedoshim) or the shevua of the Kadmonim that they used for practical Kabbala for knowledge of wisdom and the like. The Arizal answered that those sages that used the Holy Names of Hashem had the ashes of the Parah Adumah (which purifies a person from tumas meis, coming into contact with the dead) like R’ Tarfon, but we who are timei meisim are forbidden with these things.
The Chida writes, “One who wants to sanctify and separate himself from the ways of the world, even with great effort it won’t help, because of the old and new impurities... It is obvious to me that the Arizal was purified with the ashes of the Parah Adumah through Eliyahu Hanavi and then wondrous Ruach Hakodesh rested on the Arizal...”
On a similar note, Eliyahu Hanavi would bring the ashes of the Parah Adumah to the Baal Shem Tov every Erev Yom Tov in order to purify him for Yom Tov.
The Avodas Yisrael enlightens us: Through the reading of Parshas Parah, one gets a spiritual purification.
On Shabbos Parshas Parah, the Beis Aharon would say that one must believe just as the ashes of the Parah Adumah purify to offer the Korbon Pesach so too when we read Parshas Parah it purifies each one according to his level, for the light of Pesach.
In the words of R’ Tzadok Hakohen: Reading Parshas Parah helps to purify one’s heart from the impurities of the Yetzer Hara.
