Only immersion in the mikvah, following the requisite preparation, has the power to change the status of woman. When stripped to its essence, a woman’s menses signals the death of potential life. Each month a woman’s body prepares for the possibility of conception. The uterine lining is built up – rich and replete, ready to serve as a cradle for life – in anticipation of a fertilized ovum. Menstruation is the shedding of the lining, the end of this possibility.
The presence of potential life within fills a woman’s body with holiness and purity. With the departure of this potential, impurity sets in, conferring upon the woman a state of impurity or, more specifically, niddut. Impurity is neither evil nor dangerous. Within that consecrated union, the expression of human sexuality is a mandate, a mitzvah. In fact, it is the first mitzvah in the Torah and one of the holiest of all human endeavors. Moreover, human lovemaking signals the possibility and potential for new life, the formation of a new body and the descent from heaven of a new soul. In their fusing, man and woman become part of something larger; in their transcendence of the self, the draw on, and even touch, the Divine. They enter into partnership with God; they came closes to taking on the godly attribute of creator. In fact, the sacredness of the intimate union remains unmitigated even when the possibility of conception does not exist. In the metaphysical sense, the act and its potential remain linked. Human sexuality is a primary force in the lives of a married couple; it is the unique language and expression of the love they share. A strong relationship between husband and wife is not only the backbone of their own family unit but is integral to the world at large. For the blessings of trust, stability, continuity, and ultimately community, all flow from the commitment they have to each other and to a joint future. In this light it becomes clear why marital relations are often referred to as the Holy Temple of human endeavor. And entrance to the Holy always was and continues to be, contingent on ritual purity.
Woman are also commanded to immerse before their wedding day. Mikvah before marriage, strictly speaking, is not contingent upon a commitment to regular observance of Family Purity. Even so, it should not be understood as unrelated to this larger framework. And it is and awesome and auspicious way to start a new life together with one’s beloved. (chabad.org)
Leviticus 15:21-22; 15:27-28
In the Old Testament God makes many commandments to immerse in water for purity and we can specially see the importance for woman to be clean. Just like the Jewish woman still see the tevilah as an important part of their marital lives we as the bride of God have to learn to immerse in the Holy Spirit constantly. In the Old Testament we also see Jerusalem being compared to an unfaithful wife Ezequiel 16 that He cleanse (Ezequiel 16:4 and verse 9).
We also see another example of Ruth being advised by Naomi to cleanse before presenting herself to Booz (Ruth 3:3)
Jesus compares himself to a husband (Mark 2:19-20). John the baptist compares Jesus to a husband (John 3:29) The church is now the bride that he will marry one day (2 Corinthians 11:2; Ephesians 5:24-27; Revelation 19:7-9; 21;1-2). As the new wife we do not need to clean with physical water but with Living Water (Psalms 36:9; Proverbs 14:27; Jeremiah 2:13; Jeremiah 17:13; Zechariah 13:1; John 7:37-38; John 4:14; Revelation 22:1; 22:17). Today we should seek the one and only baptism that can clean us the Holy Spirit Baptism, so that we as the bride can be ready for the Groom!
Those who are left in Zion, who remain in Jerusalem, will be called holy, all who are recorded among the living in Jerusalem. The Lord will wash away the filth of the women of Zion; he will cleanse the bloodstains from Jerusalem by a spirit of judgment and a spirit of fire. Isaiah 4:3-4