The Western world has considerable difficulty with the concept of sexual intimacy. One indication is the culture's obsession with the subject. On highway billboards, in magazine ads, in best selling novels, in almost every form of cultural expression from high art to low language, sexual innuendoes dominate the landscape.

It often reminds me of that incisive quip made by Hamlet's mother Gertrude: "The lady doth protest too much, methinks." Rather than showing a free-and-easy approach to our physical relationships, this need to constantly mention the topic betrays a distinct discomfort with it.

Ironically, though the Western world has worked determinedly in the past century to free itself from every religiously imposed moral and sexual restraint, it's been left with a souvenir that sexuality is somehow dirty.

Judaism stands utterly opposed to this outlook.

In Jewish thought, physical intimacy contains within it the highest potential for spirituality. It is one of the greatest means a married couple is given to express holiness.

Like any other means, however, its use depends completely on the expression given to it by the individuals involved. The sexual union is like a canvas in the control of the artists -- husband and wife -- and the spiritual message they produce can be meaningless, or it can be a masterpiece.

Classical Jewish sources describe sexuality as a mighty river. If harnessed, it can bring irrigation and magnificent energy to countless communities. If unharnessed and out of control, it brings floods and destruction.

At its highest use -- in a Jewish marriage lived according to Jewish law -- the sexual union brings holiness into the world, as it bonds husband and wife together, spiritually, physically and emotionally.

Closeness between a husband and wife is not just a nice thing, but rather, it is the re-creation on a physical plane of a deeper spiritual reality. According to Jewish thought, a husband and wife were originally one soul before birth, split into two halves when the younger of the two was conceived. When they reunite in marriage, their bond is unique because it represents the recreation of a single entity, of one soul.

In describing marriage, the Torah writes:

Therefore shall a man leave his father and his mother and cleave unto his wife, and they shall become one flesh. (Genesis 2:24)

Yet this "oneness" that is the central goal of a Jewish marriage is not easy to achieve. By marriage age, these two half souls belong to two quite distinct individuals, who grew up with separate histories, separate experiences, separate likes and dislikes. Fortunately, marriage itself provides abundant tools to overcome these superimposed differences and establish on the physical plane the same oneness that exists on the spiritual plane.

Perhaps the most powerful of the tools that foster oneness in marriage is sexual intimacy. All the wonderful feelings a couple has in a relationship culminate in the physical intimacy between husband and wife.

If God gave intimacy this extraordinary power, it makes sense that God would give us guidelines -- a medium -- to use it to its maximum potential. Indeed, that's the case. We call this medium: Mikvah.

Mikvah -- and the accompanying discipline called "family Purity" associated with it -- were once as well known and as universally practiced in Jewish homes as lighting candles for the Sabbath. No Jewish family would dream of living without them.

Today, not only has this institution been completely forgotten by the vast majority of Jewish families, but marriage itself has lost much of its status.

In former times, however, values were different. Marriages were stronger; Jewish marriages, indeed, were the envy of the world. In those times, Jewish families not only knew about mikvah and family purity, they risked their lives to be able to practice them.

A mikvah is a spiritual tool; it has no association with hygiene.

Mikvah means collection. In physical terms, it refers to a pool that is used to collect "natural" water, untouched by human hands such as rainwater, or water from rivers and underground springs.

Culturally, a mikvah is of such significance that the rabbis of Talmud ruled that if a community has neither a mikvah nor a synagogue, building a mikvah takes priority over erecting a synagogue.

Practically, a mikvah is used by both Jewish men and women who immerse in it before certain holy acts. Though it looks like a bath, it's not: When Jewish law mandates the use of a mikvah, the user must be perfectly clean and bathed before immersion. A mikvah is a spiritual tool; it has no association with hygiene.

The Torah mentions mikvah most prominently in connection with the Jewish High Priest, the Kohen Gadol, who immersed in its waters five times during the Yom Kippur services when the Holy Temple stood in Jerusalem. Today, the most important use of mikvah is by women, who immerse in it as one step in the cycle of reunion and separation between husband and wife known as family purity.

No brief description of the practice of family purity, like the one that follows, can suffice to insure its proper practice. And indeed, no brief description of the benefits of family purity can adequately explain its beauty. Only practicing it can truly convey the remarkable nature of it.

Jewish couples who were initially unaware of the mikvah discipline, and who learned about it and incorporated its practice into their lives, have told me that if they once had doubts the Torah was given by God, then mikvah and family purity erased them. The insight, or, as they describe it, the genius of this practice is so great that no human mind could have invented it.

And yet, to the modern mind, this practice may sound strange at first because it's so different. Because this pillar of traditional Jewish life is now so foreign to us, it's often misunderstood, as we try to apply our inadequate and often shallow 21st century understanding to its extraordinary deep ways.

In the practice of mikvah and family purity, a Jewish couple separates when the wife gets her monthly period, and physical contact doesn't resume until seven days following the conclusion of her period. On the eve of the night that the couple is to resume physical relations, the woman immerses in the waters of the mikvah, where she utters a prayer inviting God to sanctify their forthcoming intimacy.

After the husband and wife wait for this time to elapse, their union represents a reaffirmation of the powers of life over death.

Essentially, the sexual union is an affirmation of life, as the couple joins together in the sacred endeavor to draw a new soul from its heavenly source into this world. Conversely, the time when a couple is allowed no contact is associated with the period of time when the woman undergoes a loss of life potential, as the unfertilized ovum is expelled from her body.

When the husband and wife wait for this time to elapse and the wife employs the mikvah before rejoining her husband in physical intimacy, their union represents a reaffirmation of the powers of life over death. It is a rising above our mortality. The cessation of physical relations between husband and wife has no connection to a feeling of revulsion over the woman's monthly flow, as is often mistakenly assumed. Such a concept has no home in Jewish sources.

Interestingly enough, though the mysteries of mikvah are bound up in this interplay between life and death, it's clear that the role mikvah plays is deeper than our understanding of life and death, because Jewish law calls for the use of mikvah even among couple for whom procreation is not possible. Indeed, Jewish law also calls for the active pursuit of a healthy, wholesome sexual relationship in married couples of all ages, and considers it an independent value -- indeed, a spiritual value -- whether or not creation of a human life is possible.

If we want to understand mikvah in depth, we must return to the references to it in the Torah. In Leviticus, chapter 16, we read about the Yom Kippur service as practiced when we had a Temple in Jerusalem.

At the apex of the service, the High Priest would enter the innermost chamber of the Temple -- indeed, the holiest space on earth -- the Holy of Holies, or Kodesh Hakodashim, where he would ask forgiveness for the nation's shortcomings throughout the previous year. No one but the High Priest was allowed to enter the holy of holies, and he himself, as the holiest representative of the holy Jewish nation, was allowed in there only once a year, for one short interval on Yom Kippur, the holiest day of the year.

It's hard to imagine today the significance of that moment. For seven days beforehand, the High Priest prepared himself for it. The night before he entered the holy of holies, a team of great Jewish leaders kept him awake all night, quizzing him and pushing him to the heights of his moral and spiritual potential. The future of not just the Jewish nation but the entire world would rest on his actions in the holy of holies - actions that were done completely in private, witnessed solely by God and himself.

After the seven days of refining himself, and after the night-long vigil, the High Priest had one final preparation to make before the awesome moment in which he would enter the Holy of Holies and effect atonement for himself, for his nation and for the world: He immersed himself in the mikvah.

The resumption of the act of intimacy of a Jewish woman with her husband is a similarly awesome moment. After her seven days preparing for that moment, a woman immerses in a mikvah in order to elevate her relationship with her husband and to elevate the world itself.

How? How can immersing in something as plain as water have such a profound effect?

Water is the most spiritual of all the physical elements. The opening passages of Genesis (1-2:22) describe the creation of many impressive things including the earth and mankind. And yet, though water is referred to ("The breath of God hovered above the face of the waters" [Genesis 1:2]), there is no mention of its creation. Our sages learn from this that water pre-existed our account of creation, and pre-existed the earth itself.

A mikvah, containing waters untouched by human hands because they either fall as rain directly into the mikvah or were fed into it via an underground spring, is the closest thing we have to a piece of heaven on earth. It gives us the opportunity to reunite with our spiritual source.

Just before a woman immerses herself in these Godly waters, she says a prayer, inviting God to sanctify her marriage -- her most intimate and important relationship.

What she says through the prayer, in effect, is: "Almighty, this is the most sacred relationship in my life. This, our conjugal union, is one of the greatest expressions of that sacred relationship, and I don't want something as sacred as this to be devoid of Your Presence. I want You to join me in this act. I want you to be there." And then she immerses and, in a sense, touches hands with the creator of the world.

The late Rabbi Shlomo Twerski, who was my brother-in-law and a brilliant Torah scholar, said that it's particularly appropriate that going to the mikvah is a woman's responsibility, as opposed to a man's, because mikvah sanctifies the family, and it is the wife's wisdom, more so than that of any other family member, that builds the home.

In a sense, a woman creates her family. For nine months before their births, she shapes a perfect internal environment for her children; then, for nearly two decades after birth, she sculpts their emotional, mental and physical environment. If she doesn't have children, she's still the one, who, in most families, will have the most creative influence on the home atmosphere and those living under her roof.

When a woman goes to the mikvah, before she returns home to exercise once again her creative intelligence, she -- the human creator -- asks for the blessings of the Creator of the universe. She asks God to come back home with her, to join her in her sacred activities, and foremost of these, to join her in her marriage.

All mitzvahs are kindnesses, and mikvah is no exception. The Talmud, which expounds on the laws in the Torah, explains a simple rule of human nature in discussing sexuality: something constantly available to us eventually loses its luster in our eyes. We allow routine to replace excitement, and grow contemptuous and bored. Boredom in marriage is no trifling matter. It is extremely destructive and in our times, it is a leading cause of divorce.

Because of this monthly "vacation," a husband and wife become like a bride and groom to one another each month, again and again.

This is the first and most obvious advantage of mikvah. For approximately two weeks every month a husband and wife are off limits to each other. Because of this monthly "vacation," the Talmud tells us, a husband and wife become like a bride and groom to one another each month, again and again. There's a perpetual freshness to the relationship; if you doubt it, ask any couple who practices mikvah and they'll confirm it, although they may blush over this truth.

Second, mikvah teaches us the value of restraint. In a world where infidelity is as common as it is today -- there have been estimates that almost one of every two married men has been unfaithful -- people have to learn the art of restraint. Unfortunately, it's not taught in school.

Within the Jewish marriage relationship, if a husband and wife can't have access to each other at regular intervals, it means they must learn to control themselves within the marriage relationship. Outside the marriage relationship, when a temptation suddenly develops and they're called upon to exercise restraint, they know how to respond. It's not as if they're suddenly called upon to run ten miles when they've never run a block.

Third, mikvah gives us the invaluable asset of "spaces in our togetherness," to adapt the poet's phrase. It affords us the opportunity to be ourselves in a way not possible if there were no separation period.

One of the primary reasons our individual souls were brought down to earth is to actualize a part of ourselves that is unique and unlike anyone else. Yet in marriage it's easy for two people to get lost in each other and not know where one ends and the other begins. This is not the Jewish ideal. The "oneness" of a Jewish marriage is not a unity of sameness, of identical mates who neither oppose nor challenge one another. Rather, it's a dynamic interaction between two individuals who maintain their identities, even though they are joined by one goal; one heart and one soul.

Two people who strengthen their individuality during this time of separation join again and enrich each other precisely because they've strengthened that part of themselves that's theirs and only theirs.

Finally, mikvah teaches us that we are not objects. Because I don't belong to you and you don't belong to me in the same way we do during the togetherness period, I'm compelled to treat you as a whole person, not as an object for my pleasure, This is an invaluable lesson in our society which, for all its obeisance to feminism, continues to treat women as objects, in advertising, at the workplace and too often in the home itself.

During the two weeks without physical contact, a couple has to learn how to talk about everything.

We also learn to communicate better with each other through mikvah. Many problems can be glossed over by a hug and kiss. During the two weeks without physical contact, a couple has to learn how to talk about everything, including many difficult things. We get to know each other's inner thoughts in ways we might not otherwise. Intimacy -- real intimacy -- is the result.

As we stated before, these benefits just scratch the surface of the spiritual effects mikvah has on our lives and on the world. There are depths to this practice we, as humans, cannot fathom. But one thing is clear:

Without serving a higher purpose, our physical intimacy is just that -- physical. With mikvah -- and God's presence -- the sexual relationship changes from something that's completely physical, an act which subhuman species also engage in, to an act of holiness and the highest expression of two people.