Parashat Ki-Teseh begins with the exceptional law of Eshet Yefat Toar, which deals with the case of a soldier who encounters an attractive foreign woman while fighting a war, and desires her. The Torah allows the soldier in such a case to marry the woman after fulfilling certain conditions. The commentators explain that the Torah enacted this provision because the soldier would otherwise be likely to engage in forbidden relations with the woman. Human nature being as it is, G-d determined that it would be preferable to permit marrying an Eshet Yefat Toar so that soldiers would not be tempted to cohabit with women in violation of the law.
This section is followed by another exceptional law the law of the Ben Sorer Umoreh, the rebellious son. The Torah commands that under certain very rare and unusual circumstances, a child who ignores his parents authority and conducts himself in an unrestrained manner is put to death. One of the requirements for a child to be considered a Ben Sorer Umoreh is Zolel Vesobeh that he is a glutton, indulging in meat and wine. The Sages explained that if a boy displays an uncontrolled lust for meat and wine, he will reach the point where he robs and murders in order to obtain the money he needs to satisfy this lust. Therefore, he must be put to death already now, in his youth, to prevent his future criminal behavior.
Our Sages offered an explanation for why the Torah juxtaposed these two subjects the Eshet Yefat Toar and the Ben Sorer Umoreh. Namely, the Torah here warns that if a person marries an Eshet Yefat Toar, he will end up having a son who is a Ben Sorer Umoreh. Although marrying such a woman is technically permissible, it will likely result in the disastrous outcome of a Ben Sorer Umoreh.
The obvious question arises as to why this is the case. True, the Mishna teaches us that Abera Goreret Abera one sin leads to another. But in this case, the man did not commit a sin; he married a non-Jewish woman in a permissible fashion, as the Torah prescribed. Why will this result in a wayward, rebellious son?
The answer, as some have suggested, relates to the well-known comments of the Ramban in explaining the Torahs command in the Book of Vayikra, Kedoshim Tiheyu You shall be holy. This command does not require us to immerse in the Mivkeh several times a day or engage in deep mystical activities. Rather, the Ramban explains, it refers to moderation and avoiding excess in our mundane activities. Technically speaking, a person can go to a casino without violating any law in the Shulhan Aruch. He can order strictly glatt kosher food, drink kosher wine that is Mebushal, make sure to pray at the proper times, and keep his Kippa and Sisit on. Nevertheless, he has failed to fulfill the Misva of Kedoshim Tiheyu. A person can meet the highest standards of Kashrut but live a very unholy life if his life revolves around food and indulgence. Living a holy life means setting reasonable limits on our physical indulgence so we can pursue loftier ideals.
This is the problem with the man who marries an Eshet Yefat Toar. He has not violated any particular law, but it cannot be considered a holy thing to do. And such conduct has a profound effect on his children.
There are two ways to educate children, one of which is very effective, and one of which is very ineffective. The ineffective but generally more intuitive way is to tell children what they should do. More often than not, this only triggers resentment and pushback. The effective way to educate children is to model the desired behavior, to show them the right way to act. Children learn far more effectively with their eyes than with their ears. They learn from watching us, not by being told what to do. The expression goes, Practice what you preach. I would suggest modifying this expression to read, Practice, and then you dont have to preach. Actions speak louder than words, and so our greatest asset in influencing our children is the personal example we set, exhibiting the kind of behavior we want our children to emulate.
This is why marrying an Eshet Yefat Toar can lead to a Ben Sorer Umoreh. It sets an example to children of what the Ramban calls, Nabal Birshut HaTorah acting improperly within the limits of Torah law. Such a thing is technically permissible, but an inappropriate surrender to desire. A child who grows up in such an environment, where the parents strictly adhere to the nitty gritty of Torah law but overindulge and place too much focus on the physical pleasures of life, can easily become a glutton, and may eventually reach the point where he resorts to criminal behavior to satisfy his lusts.
We need to teach our children not just right from wrong, but also right from right. Even within right behavior, children must be taught to distinguish between whats appropriate and whats not. And the way they learn this distinction is by observing us, their parents, exercising appropriate restraint and maintaining a healthy balance between acceptable enjoyment and excessive indulgence.