Although immersion in a mikveh, a ritual bath, before Yom Kippur is not mentioned specifically in the Torah, it is an ancient custom instituted by the prophets and continued universally to this day. As mentioned in the Shulchan Orech, the basic code of law for all Jews, it is customary for not only men and women to immerse, but even for boys and girls under the age of Bar and Bat Mitzvah.
In addition to dressing in white, not eating and praying virtually the entire day, going to the mikveh before Yom Kippur is meant to elevate us to a more expansive level of spiritual awareness. Generally speaking, immersion in the mikveh represents a transformative experience of cleansing, rebirth and return to a more pristine state, all of which are primary themes of Yom Kippur. The natural waters of the mikveh provide us with a tangibly elemental practice of returning to the limitless potential of the womb. This idea opens us up to an even deeper dimension of the Hebrew word for repentance, teshuvah, which also means to return; in this case, we are returning to our pure Divine essence, and in turn, to a deeper relationship with God.
The root of the word mikveh means, among other things, “hope.” Although Yom Kippur is certainly a most serious and awesome day, the Mishnah states clearly that it is also one of the most joyous days of the year. After ten days of intense prayer, meditation and introspection following Rosh Hashanah, each person is full of hope in anticipation of the joy of God’s forgiveness and atonement. One of the worst feelings in the world is to feel that you “blew it” and that there is no way to repair what you have wrought. Yom Kippur is understood as a veritable mikveh in time. The day itself can act as, and should feel like, a gentle stream of pure, healing waters flowing over us, rendering us completely clean. In fact, the prayers of Yom Kippur repeatedly mention this image of pure waters to poetically invoke this reality. Going to the mikveh prior to Yom Kippur helps prepare us both physically and psychologically for the spiritual experience of this great and joyous day.