In our Parasha, Dina gets kidnapped by Shechem, and her brothers Shimon and Levy come to the rescue. The Bet Yosef brings a machloket Rishonim regarding a case in which a girl was kidnapped by Goyim, if one may violate the Shabbat in order to save her. Of course, everyone agrees that if there is a risk of danger to life, whatever needs to be done in order to save her, is permitted and required. The question comes in a scenario where the kidnappers are trying to cause her to assimilate.
The Rashba says that one can’t violate the Shabbat to save someone else from sinning, since we don’t direct one to sin to prevent another from sinning. But Tosfot disagreed, saying that one must violate the Shabbat in order to bring the girl back home, arguing that it’s preferable to violate one Shabbat rather than allowing her to violate Shabbat many times, and forsaking the entire Torah.
The Shulchan Aruch concurs with the opinion of Tosfot: מי ששלחו לו שהוציאו בתו מביתו בשבת להוציאה מכלל ישראל מצוה לשום לדרך פעמיו להשתדל בהצלתה ויוצא אפילו חוץ לשלש פרסאות ואי לא בעי בית דין גוזרין עליו – One who was informed on Shabbat that his daughter was kidnapped with intent to assimilate her – it is a mitzvah to travel immediately and extend much effort to save her; even if he must traverse outside of three Parsaot. And if he does not want to, Bet Din forces him.
This was seemingly the case of Dina’s brothers who were in a position to go and save their kidnapped sister from Shechem, who wanted to marry her at any cost. The brothers kept to the halacha and went to save her by cheating and deceiving the town of Shechem, ultimately killing all the males.
But the brothers really could have taken a different route in order to save their sister; and that is to go fight a war without using any cunning ways, yet the way they chose to rescue their sister was by first weakening all the men. Though this was definitely the easier route, wouldn’t it be more ‘straight and kosher’ by fighting a war directly?
Furthermore, we find later in the Parasha that their father Yaakov didn’t agree with their approach of deceiving the town’s people. Raising the question, what would he have done differently?
Rabbi Shlomo Zalman Aurbach wrote a psak halacha about a person who was very ill—to the extent which warranted violating Shabbat on his behalf, who needs to drink tea but doesn’t have any hot water, stating that it would be permitted to boil water for him.
What would be the halacha if the neighbor has tea ready, but is already sleeping? Would it be allowed to violate the Shabbat and prepare the tea or should the neighbor be woken up to in order to avoid Shabbat violation?
A similar case regarding a gravely ill person who needs light in the room and the sleeping neighbor has a lamp that could be brought without violating the Shabbat (moving the light is normally Muktse), would one be able to turn on the light or must the neighbor be woken up?
In both cases, R’Aurbach ruled that one may violate the Shabbat and the neighbor need not be awoken, to obtain the tea.
In another instance, where the electric wires in the street ripped on Shabbat, posing a risk of someone accidentally touching them and get an electric shock. There too, it was ruled that one may contact the electric company to come and repair the downed wires, and there is no need to disturb a Jew to stand by the wires throughout the Shabbat in order to warn people.
After his psak was written in the famous sefer Shmirat Shabbat Kehilchata, some of the big rabbis in Israel argued saying it’s a mistaken psak that shouldn’t be followed. The rationale being that the neighbor is commanded in saving a life, just like everyone else, despite any inconveniences he may incur. Thus, he too must be woken up and help. Same with the downed electric wires, it’s not permitted to phone the electric company to come down to fix the wires, rather people must stand by the wires to make sure no one gets hurt.
Rabbi Aurbach wrote back a lengthy response defending his ruling. He brought such cases from the Shas showing that when one is permitted to violate the halacha, he can do so even if there is a way to prevent doing so but it’s harder to do.
For example, a Cohen (which isn’t allowed to walk into a cemetery), who comes across someone who needs to be buried, and there is no one else around to bury him, may deal with the corpse and go into the cemetery to bury him. He may do so himself even if someone else may be hired to deal with the corpse in his stead, as he isn’t obligated to spend his money if the only way for him to have someone else bury the dead would be with a payment. This is because the Torah permitted the Cohen to become tameh in order to bury in such case.
Although generally, one must give up all his money to prevent sinning, but that is only when one isn’t permitted to sin; in a case of this Cohen, he may become tameh unless he finds someone who’s willing to take his place for free.
Rabbi Zilberstein was asked by a doctor about a case he had on Shabbat, where a woman in labor had to go through an immediate, lifesaving procedure that normally requires the husband’s signature of consent, lest the operating doctor be sued.
The doctor wanted to know if he can contact the husband (which would constitute violating Shabbat), or must he go on with the procedure without obtaining consent, risking possible litigation and all the aggravation and legal fees this entails?
The Rabbi brought the opinions we mentioned above, and explained that it might be allowed based on the above reasoning to bring the husband down to the hospital for all that is necessary.
After learning the halacha on life-threatening matters, that one may approach it with the way that is easier for him, we can conclude that since the brothers had an obligation to rescue their sister Dina, they also could have chosen the easier way for them, which was to trick the town of Shechem with the Trojan horse of a “peace treaty” to defeat them and bring back Dina.
[To understand why they also killed the males see the explanation of the Rambam and the Ramban.]
Concerning the disagreement of the brothers and Yaakov, perhaps we can say that it came from different approaches of how to save Dina, based on a known machloket regarding where the mitsvah of saving one’s life is derived from.
The Chochmat Shlomo wrote that we know the mitzvah of saving lives from where the gemara learns it, the mitsva of returning lost objects to their owner, השבת אבידה. The Gemara says that just like one must return a lost object to its owner, so must he make sure to return his life (or protect it) if it’s in jeopardy. According to that we can follow what the mitzvah of השבת אבידה teaches, which is that one doesn’t have to spend his own money in order to return a lost item or embarrass himself while returning it and not put himself in danger for it. If that’s the case, the same would apply to save one’s life (since we learn it from saving one’s property and therefore, they must have the same rules).
Many argued on his opinion feeling that we learn saving one’s life from the pasuk לא תעמוד על דם רעך. According to this, it doesn’t have the guidelines of the mitzvah of השבת אבידה.
Perhaps we can explain the difference between the approach of the brothers, and that of Yaakov Avinu, with the difference of opinions of where we learn the mitzvah of saving a life. According to the brothers, we learn it from the mitzvah of returning lost objects and therefore fall within the parameters of the Mitzvah, which doesn’t obligate us to do so if there is a risk, thus they decided to cheat them with a false deal.
Yaakov Avinu on the other hand, learned the matter of saving a life from that of לא תעמוד על דם רעך and therefore felt they had no right to deceive, just to get their way.
 סוף סימן שו
 ח״ז סי’ רסז
 שבת ד
 סוף סימן שו סי״ד
 ראה יונתן בן עוזיאל שכתב שיקחוה בחזקה כנגד רצונם, דהיינו ע״י מלחמה
 פרק לד, ל
 פל״ב סעיף סה
 מנחת שלמה קמא ס״ז
 יו״ד סי’ שעד ס״ג
 או״ח סי’ תרנו
 שעורי תורה לרופאים ח״ב עמוד 279
 הגהות לחו״מ סי’ תכו
 סנהדרין עג,א