The Talmud (Shabbat 21b) records the different opinions of the Academy of Shammai and the Academy of Hillel regarding lighting the Hanukkah lights:
According to Beit Shammai we light eight candles on the first night, seven on the second night, six on the third, and so on, decreasing by one each day until lighting one candle on the eighth and final night.
According to Beit Hillel we light one candle on the first night, two on the second night, three on the third, and so on, increasing by one each day until lighting eight candles on the eighth and final night.
The Talmud continues by quoting the sage Ulla, who cited two explanations for this difference, two explanations given by two Amoraim, both of whom lived in the Land of Israel.
The first Amora was Rabbi Yossi bar Avin: according to his explanation, Shammai saw the candles as corresponding to the days still to come, hence eight candles on the first night, seven on the second night, and so on until one candle on the eighth and final night when there is only one day left.
Hillel, by contrast, saw the candles as corresponding to the days which had already come, hence one candle on the first night, two on the second, and so on until eight candles on the eighth and final night.
The second Amora was Rabbi Yossi bar Zavda (or Zavida). According to him, Shammai saw the Hanukkah candles as paralleling the bulls which were sacrificed on Sukkot, which diminished from thirteen bulls on the first day of Sukkot, to twelve on the second day, and so on down to seven bulls on the seventh and final day of Sukkot (Numbers 29:12-34).
Hillel, by contrast, applied the principle that מַעֲלִין בַּקֹּדֶשׁ וְאֵין מוֹרִידִין, “we increase sanctity, and we do not decrease it”.
According to Rabbi Yossi bar Avin, Shammai emphasizes the potential (the days still left to come in the future), while Hillel emphasizes the actual (which night of Hanukkah this is).
This is consistent with Hillel’s and Shammai’s opinions throughout the Talmud: Hillel’s interpretations of Halakhah always reflect the actual, Shammai’s always reflect the potential.
In other words, Hillel sees the world as it is; Shammai sees the world as it should be.
In this, as in almost all disputes between Hillel and Shammai, we follow Hillel’s opinion. (There are just nine exceptions in the entire Talmud – six cases in which we follow neither opinion, and three in which we follow Shammai’s opinion.)
The Talmud (Eiruvin 13b) records that “for three years the Academy of Shammai and the Academy of Hillel disputed, each one claiming that ‘the halakhah follows us!’. A Heavenly Voice came forth, proclaiming: Both are the words of the Living G-d – and the halakhah follows the Academy of Hillel”.
The Yerushalmi (Berachot 1:4, Yevamot 1:6, Sotah 3:4, and Kiddushin 1:1) cites the same episode, and provides an additional detail: “Where did this Heavenly Voice come forth? – …In Yavneh”.
“In Yavneh” – meaning after the destruction of the Holy Temple, after the Sanhedrin had relocated to Yavneh from the Chamber of Hewn Stone at the entrance of the Holy Temple.
When will Beit Shammai’s opinion constitute practical halakhah? – The Zohar (Ra’ayah Meheimnah Volume 3, Parashat Pinchas 245) explains that Hillel’s opinion is appropriate for this world, while Shammai’s opinion is reserved for the days of Mashiach.
That is to say: in today’s imperfect world, we follow Hillel’s rulings.
In the future time to come, in the days of Mashiach, when the world will be perfected, when today’s potential will become the actual, we will light eight candles on the first night of Hanukkah, seven on the second, and steadily diminish until we will light one candle on the eighth and final night.
And so this Thursday afternoon, as I prepare my Hanukkah Menorah for the first night of Hanukkah, I will fill eight vials of olive oil ready for lighting. Because I don’t know what might yet happen in the next couple of hours before nightfall. And I want to be ready for anything that may happen.
And maybe, just maybe, before sunset…