In which is explained:
- Why we are required to light the Chanukah lights only for about half an hour, and not the whole night.
- How the different opinions about the length of time that we are required to light conform precisely with the different opinions concerning the length of bein hashmoshos (twilight).
The gemora in Shabbos 21b teaches that the amount of oil which is required for Chanukah lighting is the time period from sunset until there are no more passersby outside.
But there are several opinions about how long this time period is - the Rambam says that it is about half an hour or a little more, the Shulchan Aruch says that it is about half an hour, and a third opinion says that it is 24 minutes. And because we know that the shiurim which Chazal taught us are very precise, we wish to understand the reasoning behind these different opinions, in particular the unusual wording of the Rambam “about half an hour or a little more”.
But first we have to answer a different question - why did Chazal establish this festival of Chanukah with praise and thanksgiving because of the open miracle which they experienced at that time, that one day’s worth of oil miraculously lasted for eight days? Surely they saw such a miracle on a daily basis with the Ner Ma’arovi, which only had enough oil to last the whole night like all the other lamps but nevertheless miraculously carried on burning also the whole day! How was the miracle of the oil of Chanukah different from the miracle that they were accustomed to witness every day?
To answer this question we first need to remember that every day the Kohanim had to put enough oil in each lamp for them to burn the whole night until the morning. And because there is a question as to whether the period of bein hashmoshos (twilight) is day or night, they needed to light the menorah before this time. Chazal calculated that the total amount needed was half a log of oil, and so this was the amount which they placed in all the lamps (including the Ner Ma’arovi) each day before bein hashmoshos. Thus, the amount of time that the Ner Ma’arovi miraculously burned during the daytime was a whole day (12 hours) minus the time of bein hashmoshos.
Returning to our original question, if Chazal had wanted to establish the festival of Chanukah because of the miracle that the oil burned all night for eight days, they almost certainly would have commanded us to light the whole night as a remembrance of the miracle. But if they had done so it would not have been very clear that we are celebrating the special miracle of Chanukah, since part of this time period - 12 hours minus bein hashmoshos - was a miracle they saw every day with the Ner Ma’arovi.
Therefore, Chazal instead wisely established the lighting of Chanukah lights for the amount of time that the miracle of the oil of Chanukah exceeded the miracle of the Ner Ma’arovi. This comes out to be twice the time period of bein hashmoshos, because the Ner Ma'arovi miraculously stayed alight for 12 hours minus the period of bein hashmoshos, and during the eight days of Chanukah the lamps miraculously stayed alight for 12 hours plus the period of bein hashmoshos. Thus it is now clear why Chazal commanded us to light the Chanukah lights for a period twice that of bein hashmoshos.
Now, with regard to the length of the period of bein hashmoshos there are three opinions. The gemora in Shabbos 34b writes that Rabbah in the name of Shmuel taught that it is the time it takes to walk 3/4 mil, but R. Yosef in the name of Shmuel taught that it is 2/3 mil, and the Rosh writes that the halachah is like R. Yosef. And according to the Rambam it takes 24 minutes to walk a mil, but according to the Vilna Gaon (and this is the halachah) it takes 22 and 1/2 minutes. There is also a third opinion that it takes 18 minutes.
Now we see clearly how the three opinions concerning how long we are required to light the Chanukah lights are in complete accordance with the opinions concerning the length of bein hashmoshos. Because according to the Rambam who holds that the mil is 24 minutes, bein hashmoshos (2/3 mil) is 16 minutes. Thus, since the miracle of the oil of Chanukah exceeded the daily miracle of the Ner Ma’arovi by twice the period of bein hashmoshos, we are required to light for 32 minutes. Thus we see how beautiful and careful are the words of the Rambam. who taught that we are required to light for half an hour and a little more.
And according to the halachah which follows the opinion of the Vilna Gaon, the length of bein hashmoshos is 22 and 1/2 minutes, 2/3 of a mil is 15 minutes, and twice this amount is 30 minutes precisely, neither more nor less. Thus the Shulchan Aruch teaches that we are required to light for half an hour. And according to the third opinion that the mil is 18 minutes, 2/3 of a mil is 12 minutes, and thus twice this amount is 24 minutes.
Hence we see that the three opinions concerning how long we are required to light the Chanukah lights precisely match the three opinions concerning the length of bein hashmoshos. Amazing!