How do you know that Yaakov wore a streimel? Because the pasuk says ‘and Yaakov went out,’ and he would not have gone out without a streimel! That is the popular joke [popular depending on one’s sense of humour I suppose], but it does raise a serious issue. This issue is a bit less practical than what we normally speak about but a bit more interesting. The Avos were commanded to keep the seven noachide laws and indeed kept them, but they were not commanded about most of the other mitzvos and so any observing of these mitzvos would be voluntary. Thus the question is did the Avos keep the Torah before it had been given? Here is the conundrum
: The mishna and gemarra clearly say that Avraham kept all the Torah. He knew the Torah because he had ruach hakodesh, which may be explained here in that HaShem created the world to match and reflect His Torah, and Avraham simply had the expertise to reverse the process; he looked into the world and understood its spiritual message and deduced the Torah from there – much like looking at a building and working out the blueprint. Yet there are several examples of the Avos (and others) going against that which the Torah commands; Yaakov married two sisters, Kayin married his sister, Yaakov made Yosef the firstborn over Reuven the biological firstborn, and Amram married his aunt Yocheved. So did they keep the entire Torah or not?
There are two approaches here; one is to say that they did not keep the Torah (and deal with the mishna and gemarra above) and the other is to say that they did keep the Torah but the above cases are exceptions. We shall cite the various opinions[some which answer only part of the examples], as well as some difficulties that each point out in others’ explanations, and shall end with a short lesson.
First up to bat is the ‘they didn’t keep all the Torah approach.’ The Rema writes that only Avraham kept all the Torah and not the other Avos. Seems a simple enough answer, but no-one else went with this answer, because it is not so logical to say that Avraham kept the entire Torah but his son Yitzchak did not follow in his father’s footsteps, and also there are several sources which show that others knew and kept the Torah too. Next, the Ramban’s answer is that the Avos only kept the entire Torah in Eretz Yisrael, and Yaakov married the two sisters [and refigured the firstborn] in chutz l’aretz; this is why Rachel died on the way to Eretz Yisrael. It is implicit that Rashi argues with this answer, because in this week’s sedra he explains Yaakov’s message to Esav to be ‘I kept all the mitzvos even in the house of Lavan;’ Lavan did not live in Eretz Yisrael and even so Rashi says that Yaakov kept all the mitzvos there. Moreover, the Maharal rejects the Ramban’s explanation by asking that the prohibition to marry two sisters has no inherent connection to the Land of Israel so why should Yaakov’s whereabouts affect this? Either way, for Rashi at least we need a new answer; you be the judge if any of the other answers fit for Rashi.
The answer of the Maharal himself is that the Avos only kept the positive mitzvos but not the negative mitzvos. The reason is, he explains, that one can still get reward and achieve spiritual results for keeping positive mitzvos even when not commanded (eg a woman shaking lulav), but breaking a negative commandment is only spiritually damaging when it goes against something HaShem has commanded us not to do. And since the Torah had not been given yet, the Avos had not been commanded by HaShem about the negative prohibitions; not to marry two sisters, for example. Finally in this section is the opinion of the Rambam. He writes that the Avos did not keep the mitzvos, but rather got to their lofty spiritual level by ‘having understood everything there is to understand in true wisdom and corrected themselves in every way.’ What the Rambam means, as explained by Rav Osher Weiss, is that the way that the Avos kept mitzvos was completely different to how the mitzvos were to be kept after the Torah was given. Each mitzvah achieves a certain spiritual effect/tikun, but the Avos had the ability to be able to tap into creating these effects and tikkunim without necessarily performing the technical details of the mitzvah.
The next section is the approach that the Avos kept all the mitzvos, and the cases of the Avos seemingly breaking prohibitions are to be re-understood. First is the Ridbaz, who says that only the Avos kept the entire Torah (so no question from Kayin or Amram), and the reason that Yaakov could marry two sisters is based on the dictum that a convert to Judaism is considered like a newborn baby, and as such they are not considered halachically related to their former family. Thus, when Rachel and Leach converted and married Yaakov, they were no longer considered sisters and thus there was no problem for Yaakov to marry them. Our next answer is courtesy of the Or HaChaim, who writes that the Avos knew and kept the entire Torah, but the discrepancies above were instances where they received a specific prophecy not to keep a certain commandment, which is fine as it is only a [prophetic] temporary suspending of a mitzvah. Thus, HaShem told Yaakov that in this instance he was to marry two sisters. Similar to this idea is the answer of the Da’as Zekeinim and Nefesh HaChaim that just like the Avos knew the Torah and its mitzvos through ruach hakodesh (Divine/holiness of spirit and wisdom for lack of a better term), they also saw via ruach hakodesh that in specific situations there would be a great benefit which allowed them to ‘deviate’ from the Torah. Examples of this ‘great benefit’ are marrying two sisters in order to build Klal Yisrael, or the specific insight of Yaakov to realise that Yosef was more spiritually befitting the firstborn status than Reuven. Once the Torah was given, however, the commandments were to be kept unswervingly with no regard to any perceived ‘great benefit’ in failing to observe them. In fact, the Nefesh HaChaim there says that this is one reason for HaShem not giving the Torah to the Avos; for if so the calculations of the Avos in determining situations spiritually beneficial to be able to go against a commandment would be negated and irrelevant if the Torah had been given, and so Yaakov would not have been able to marry two sisters and build Klal Yisrael.
We shall end with the answer of the Lubavitcher Rebbe. He has a different definition of the ‘great benefit’ that allowed the Avos to ‘go against’ the commandments in certain situations, with specific reference to Yaakov’s marrying two sisters. The great benefit was that Yaakov had made an open commitment to marry Rachel, and it would hurt her if he were not to go ahead and marry her as promised. From here we see, said the Lubavitcher Rebbe, how important it is not to harm others’ feelings, and especially not to let our religious behaviour and practices be the cause of hurt for others. What impressed me was the sign posted on the Shul next door on erev Shavuos, in preparation for the customary all-night learning of Shavuos [tikun leil]. The sign reminded people to make sure they do not learn too loudly for it might wake the neighbours and read ‘let our tikun not be a kilkul’ (let our tikkun leil not be destructive for others.’) Another example of this principle is the issue of aeroplane minyanim; some Rabbis have said that it is better for people to daven in their seats because of the disturbance that the minyan causes to others. Finally, when the kohen gadol is in the holiest place on Yom Kippur one would expect him to say a long prayer; after all it is only once a year that he is there. Yet we are told that he said just a short prayer in order not to scare the people that they might think he had died. This shows the importance of caring for others’ feelings even at the holiest of moments.
Those are seven answers to our question. Though there was a lot of information packed in, I hope we gained a practical message from the last part too,
Have a great Shabbes!
 Ramban Berieshis 26;5, amongst others.
 Against the Torah prohibition in Vayikra 18;18
 Gemarra Sanhedrin 58b
 Against the Torah prohibition in Devarim 21;16
 Most of these sources were gleaned from Rav Osher Weis’s ‘Minchas Osher,’ parshas Vayishlach, and I looked them up
 As in Rav Mosher Isserlis, in Shut (responsa) Rema siman 10
 The Ramban in Bereishis 26;5 brings the sources; about Yosef having learnt Torah with his father Yaakov and keeping Shabbes in Egypt, Yehuda fulfilling the mitzvah of yibum, and Noach knowing the Torah. See Rashi Bereishis 7;2 and 45;27 who quotes some of these sources. Obviously, the Rema knew these sources too, and so must have had answers.
 Ramban Bereishis 26;5
 Rashi Bereishis 32;5
 However, according to the Divrei David brought by the Sifsei Chachamim on Rashi there, Rashi merely means that Yaakov learnt all the mitzvos of the Torah during his time with Lavan, and we have a principle that to a certain extent learning a mitzvah is like fulfilling it (like saying korbanos is like offering up a sacrifice; gemarra Menachos 110a). The introduction to Eglei Tal echoes this principle. According to this, Rashi is not necessarily arguing with the Ramban.
 Gur Aryeh Bereishis 46;10 (and 32;4), and Maharal Chiddushei Aggados Chullin 91a
 To be found in Iggros HaRambam; Iggeres LeRav Chisdai HaLevi L’Alexandria. Apparently, this is also the opinion of the Oneg Yom Tov in his introduction, as well as Rav Avraham ben HaRambam al HaTorah
 Shut Ridbaz 696, as well as the Maharsha Yoma 28b ‘mitzvosai’
 Gemarra Yevamos 22a
 Or HaChaim Bereishis 49;3
 Da’as Zekeinim of the Ba’alei HaTosfos, Bereishis 37;35
 Nefesh HaChaim by Rav Chaim Volozhin, sha’ar alef chapter 21
 I heard it repeated by a Chabad Rabbi; I have not read it in the Rebbe’s sichos myself.
 Rav Shlomo Zalman Aurebach. Rav Shwab did not used to join the minyan at the back of the plane, and neither does Rabbi Frand. Each person should ask their own Rabbi.
 Mishnah Yoma 52b