[The rabbis note that the events of Chanukah] occurred in the 160s BCE, and the books that recount them are not part of the Hebrew Bible. This means that the holiday of Hanukkah is not a biblical but a rabbinic institution; and as we have seen before, rabbinic decrees are of lesser authority than biblical ones.
This explanation is not commonly known in Messianic Jewish circles, where the rabbis are often accused of usurping divine or Biblical authority. But such accusations rarely acknowledge the Deuteronomy passage referenced above, where authority to interpret the difficult questions raised by the Torah's teaching is actually delegated to the judges of Israel.
This leads the Talmud to note an anomaly in the Hanukkah blessings. We praise God “who commanded us to light Hanukkah lights”: “But where,” the Gemara demands, “did He command us?” In fact, it was not God but the rabbis who commanded us to do this. Still, the Talmud attempts to reconcile this fact with the words of the blessing. Rav Arya cites a verse from Deuteronomy: “You shall not deviate from the word that they will tell you.” In context, “they” are the priests and judges of ancient Israel; but the rabbis see themselves as the priests’ inheritors, and they read the line as commanding obedience to all rabbinical decrees.
Is this authority then unlimited? Interestingly, the Talmudic passage recognizes this very same question, continuing beyond the above logic to a more reserved conclusion. Kirsch writes:
By this logic, however, everything the rabbis ordain should be considered just as sacred as what the Bible decrees—as the Gemara goes on to point out. The argument is finally settled by the common-sense opinion of Abaye: The blessing on Hanukkah is not absolutely required, but it is instituted “so that people do not treat [the holiday] with disrespect.” It follows that biblical holidays still take precedence over rabbinic ones: If a poor man has to choose between buying Shabbat candles and Hanukkah candles, the Talmud says he should pick the former.