The Foundation Stone Haggadah: Reb Tzaddok: Rachtza
Rav Tzadok Hacohen of Lublin asks, why do we say, “…who sanctified us with His commandments,” before we perform a mitzva? He answers that it is because object of the mitzvot is to sanctify us, or to allow ourselves to be sanctified. Again, what does washing our hands represent? – Teshuva. And where did the Kohanim wash their hands? – In the wash basin. In the Tabernacle, the wash basin was constructed from the mirrors of the women who used them to make themselves beautiful and so that they could seduce their husbands. In fact, when Moshe saw these mirrors he said, “Are you guys nuts? This is supposed to be a House of God! And you’re bringing your cosmetic mirrors? Get out of here!” God says to him, “One minute Mo, that’s exactly what I want in the Tabernacle.”
In other words, the idea of Kedusha is not to withdraw from the world, but to use it in a way that sanctifies it. I believe that the idea behind Rachtzah, though I don’t have a source for it, is to remember the mirrors of these women. We must know that the way to sanctify ourselves is to be involved with the world and learning to make it holy. If we have to withdraw from the world to find holiness, then we are not free. To be sure, the struggles we experience in the world can crush us and take away our sanctity. Therefore, the only way we can live in the world and remain free is through Kedusha. That’s why when we wash our hands on Seder night we are, in effect, re-enacting the washing of the priests in the wash basin made from the women’s mirrors.