By Rabbi Berach Steinfeld
Lighting a menorah in the Bais Haknesses and reciting a bracha on it is mentioned in Shulchan Aruch, Orach Chaim, siman taf resh ayin alef, seif koton yud alef.
There are a few reasons for this minhag. The Bais Yosef in siman taf resh ayin alef explains that there may be some travelling guests who don’t have a house in which to light. The same way Chazal established that Kiddush should be recited in Shul, they were mesaken that neiros Chanukah should be lit inShul as well.
The Bais Yosef in the name of the Rivash gives another reason for this minhag. The proper way of doing the mitzvah would be to light theMenorah outside one’s door, towards the Reshus Ho’Rabim; however, since we are in Galus we aren’t able to do this, so we light in Shul instead to be mefarsemthe Nes.
The Kol Bo says that lighting the menorah in Shul is a zecher to the lighting in the Bais Ha’Mikdosh, which was done in public.
The question arises; why are the neiros Chanukah lit in Shul in the morning, which was not the correct time of lighting?
There are a few answers to this question. One answer is that the pirsum ha’nes is apparent if the menorah is lit during the day rather than at night. If it is lit at night people may think that the lighting of the neiros is to add light because it is dark. However, when it is lit during the day no one can be mistaken into thinking the menorah was lit for any other purpose than to proclaim the nes.
Another reason for lighting during the day could be if one was travelling and did not light the night before, he will now know how many candles to light the coming night.
A third reason could be that we want to be yotzei the opinion of the Rambam who holds in Hilchos Temidin Umusafin, Perek Gimmel, halacha yud and yud bais that there was a requirement in the Bais Ha’Mikdosh for the Kohen to relight the candles in the morning if he found them extinguished. Therefore, in the Shul, which is similar to the Bais HaMikdosh, we light during the day to remind us of the halachos that were required in the Bais HaMikdosh.