Question:

Our family is modern Orthodox. I try to instill in my wife and daughters an appreciation for the laws of modesty, but it always leads to arguments. My wife says that wearing a blouse that reveals the cleft of the chest is the unspoken dress code in the office where she works, and my daughters always answer that all of their friends dress according to the going fashion and they don't want to be the ugly ducklings in their crowd. My question is, how strict can I be if it leads to tension and quarrels at home?

Answer:

The renowned Torah scholar, Rabbi Shalom Elyashiv, says that the issue of modesty is not to be seen as a demand from a man to his family, but rather a halachic requirement like all of the other laws in the Torah. This means that if there is a question of what is the proper style of clothing to wear, a qualified rabbi must be consulted, just like when there is a question in any other detail of the law.

Also, since daughters are influenced by the behavior of their mothers, it is important that the mother conform to the proper, halachic standard of dress for her daughters to follow.  If she dresses in opposition to the ways of Jewish modesty, then it is not reasonable to expect that the daughters will behave otherwise. If this means that the mother might lose her job, this is a risk that must be taken in order to safeguard the Jewish law and the sanctity of the family and the marriage.

Modesty should not be an angry decree...

It is important to inspire one's family to understand that the principles of Judaism far outweigh any passing fashion. It is important to teach one's family that it is more important to please Hashem, then to please the men in the office, or the guys and girls at school.

The halachic authority, Rabbi Moshe Shaul Klein, emphasizes that women should be made aware that infractions in modesty have not only personal consequences, but public consequences as well. A woman who goes out to the street wearing clothes that draw attention and show off her body, not only brings punishment on herself for violated a commandment, but she also brings others to sin.

Regarding this it is written, whoever brings the multitude to sin will not be afforded the chance to repent. For if this woman causes a man to stray from the right path with improper fantasies and actions, even if the woman repents for her errant behavior, all of the sins of the men she tempted still rest on her head. When she appears before the heavenly tribunal at the end of her life, she will have to give an accounting for all of her deeds, and she will discover that she is accused of myriads of transgressions, things that she never even thought to do.

Immodest dress can cause traffic accidents and other public hazards

Furthermore, the masters of Kabbalah have longed warned us that one of the major causes of the tragedies and sufferings that come upon us is due to breaches in modesty. When women dress in opposition to the tenets of Jewish law, destructive angels are created that wreak havoc in revenge. Then it is too late to ask, "Why has this tragedy come upon us?"

By explaining these things in the proper fashion to one's wife, and according to the age and intellectual capacity of one's daughters, in order to enlighten, and not to invoke thunderbolts and lightning from out of the sky, a new respect and appreciation for the laws of modesty can be achieved in the home, for the betterment of the family and the Jewish People as a whole.

Two random examples of books on modesty are:
1. Modesty: An Adornment For Life by Rabbi Pesach Falk
2. Understanding Tzniut by Rabbi Yehuda Henkin