family purity

Hi,

I understand from your question that you are interested in the mitzvah of family purity this is a special mitzvah which is intrinsic with the sanctity and specialness of the jewish family which our mothers and grandmothers have kept strongly for thousands of years.

The mitzvah,

Jewish law forbids a husband to approach his wife during the time of her menses, generally from five to seven days, and extends the prohibition of any physical contact beyond this period for another seven days, known as the “seven clean days.” During this time husband and wife are expected to act towards each other with respect and affection but without any physical expression of love. At the end of this twelve to fourteen day period (depending upon the individual woman), the menstruant (known as niddah) must immerse herself in a body of water known as a mikvah and recite a special blessing in which she praises G d for sanctifying us with His commandments and commanding us concerning immersion (tevillah).

By thus preparing for their wedding and afterwards for their monthly marital reunion—separating from each other and then, before joining each other, the wife immersing in the mikvah, and reciting thereupon the blessing thanking the Al-mighty for sanctifying us through this institution—husband and wife acknowledge, in the most profound symbolic manner, that their relationship is sanctified and blessed, that it is pure and not vulgar, sacred and not salacious. Family purity has a magnificent cleansing effect upon the psyche. It purifies and ennobles the outlook of man and woman upon each other and their relationships to each other.

The blood of nidda was a result of the sin of chava -Eve eating from the tree Yet this prohibition is not necessarily understood intellectually and although there are different explanations given for the mitzvah of family purity we truly do not know the reason why it is forbidden.

However there are some clear physical benefits from keeping this mitzvah

Amongst them

Taharat ha-mishpahah – family purity is also crucial in protecting the marital bond from one of its most universal and perilous enemies which comes to the fore soon after the newness of married life has worn off: the tendency for physical relations to become routinized.

It is easy enough to get married. It is quite another thing to stay married…

For Unrestricted approachability leads to over-indulgence. And this over-familiarity, with its consequent satiety and boredom and ennui, is a direct and powerful cause of marital disharmony. When, however, the couple follows the Torah’s discipline and observes this period of separation, the ugly spectre of over-fulfillment and habituation is banished and the refreshing zest of early love is ever-present.

There is so much insight in this comment of the rabbis! Familiarity does indeed breed contempt, and a little absence does make the heart grow fonder…

With the institution of taharat ha-mishpahah… the drama of love-without physical contact followed by the loving union of husband and wife and their being together is repeated every month. Thus the separation of husband and wife physically during the period of niddah and the “seven clean days,” when they may express to each other feelings of tenderness without any physical contact, is equivalent to the period of engagement. Then, just as she did when she was a bride, the wife undergoes the immersion in a mikvah, recites the same blessing she did as a bride and comes to her husband, in purity and love, as she did on her wedding night…

A important note:

There are some people who imagine that voluntary separation will accomplish the same result, and that it is therefore unnecessary to follow the whole pattern laid down by Jewish law. But such voluntary separation ultimately proves inadequate. One partner may suspect coldness on the part of the one who proposes the withdrawal. Moreover, a lack of religious sanction means that the entire separation will no longer be elevating and ennobling as it can be only when it is informed by religious significance.

In summary

The reasons for this we mitzvah we do not know but we do it because this is g-ds desire in addition by fulfilling this mitzvah there are many side gains as I have mentioned

I would strongly recommend that you do follow up reading on Chabad.org from where I generated a big portion of this article.