The Gemara in Shabbos and Succah quotes 2 pesukim that show that rabbinical mitzvot (the context is the lighting of Chanukah Candles) are from the Torah. My question is, the 2 pesukim quoted taken out of context, Devarim 17:11 and 32:7. The second one is very out of context, but the first one makes more sense, but the context is a court case too hard for you, not just Stam. Please clarify, either maybe my understanding of the pesukim is wrong, or maybe the Rishonim/Achronim give a different answer. Also, why isn’t it Baal Tosif

ב"ה Shalom, While you question is an important one, this is the type of question asked while studying in Talmud in depth and although I will a give a concise answer here, I strongly suggest that you pursue your question with leaned Rabbi and colleagues in the Bet Hamidrash. Your question touches upon the time-honored dispute between the RambaM and the RambaN in our regard to Rabbinical decrees. The Rambam (הלכות פרק א הלכה ב, ספר המצוות שורש א ) says that when on transgresses a Rabbinical decree, he transgresses the mitzva of לא תסור . The Ramban ((בהשגות לספר המצוות, שורש א') disagrees and argues if that is the case , it makes every Rabbinic transgression a Torah transgression, and asks how one can be lenient in regard to Rabbinical ordinances. The issue is discussed by many Achronim. In the "Machloket" between Rav Avia and Rav Nechemia in Shabbat 23. , the Ran and the Ritva on that Germara seem to indicate that the quote from the Devarim 32:11 שאל אביך ויגדך comes to tell us that Rav Nechemia doesn't agree with Rav Avia's position of anchoring the Bracha for lighting candles on Chanuka (or any other Rabbinic ordinance for that matter ) on the Negative commandment of לא תסור for something which has no basis in the Torah. But he rather quotes the passuk שאל אביך to indicate a general adherence to listening to the words of our elders and scholars. (See also מהר"ם שיק מסכת שבועות דף כד עמוד א) Rav Kook zt"l (עין אי"ה שבת דף כג אות כה) also expounds this idea from a spiritual point of view. He says the passuk שאל אביך come to teach us never to disassociate ourselves from our past, because our past is great and Divine and from there the Chachamim of each generation derive the source of their ordinances. Your question in regard to "בל תוסיף " is another broad issue, but again I will answer in short. According to the Rambam (הרמב"ם בהלכות ממרים פרק ב', הלכה ט') the prohibition of בל תוסיף only applies only if the Bet Din which makes the ordinance claims it is "D'oraita" – torah binding, but if it was made as a mitzva of Chachamim there is no prohibition. See also Rashba to Rosh Hashana דף טז, who says that when Chachamim make an ordinance out of necessity it doesn't come under the prohibition of Bal Tosif. All the best חג כשר ושמח