However, in the popular mind, this is not how Judaism works. Oftentimes there are customs that in people’s minds far supersede their technical, halakhic importance. The greatest example of this is Mourner’s Kaddish, a custom that does not appear in the Talmud and took quite a long time to fully develop. From a technical, source-oriented, halakhic perspective Kaddish is not particularly important. But of course, in actual practice, for most people the recitation of Kaddish is the most important aspect of mourning.

There is a practice alluded to in this week’s parashah that I believe also fits into this category, a practice which is at best alluded to in classical sources, is found in only a few medieval halakhic books, but which plays a prominent role in Jewish lives and probably has for a long time. The first verse of this week’s parashah reads, “You shall further instruct the Israelites to bring you clear oil of beaten olives for lighting, for kindling lamps regularly (ner tamid).” On many occasion, someone has come up to me in a synagogue and said, “Rabbi,” (to which I instinctively reply that I am not a rabbi), “the light on the Ner Tamid is out.” When they come into the synagogue many Jews are quick to notice the Ner Tamid, and if it’s out, someone, usually the rabbi, is going to hear about it.

But where does this custom come from? Does the Ner Tamid have to always be lit? Professor Israel Ta-Shema addresses the history of the Ner Tamid in an article in which he discusses the transfer of Temple law to the synagogue. In Ezekiel 11:16, God says, “I have indeed removed them far among the nations and have scattered them among the countries, and I have become to them a lesser sanctuary (mikdash me’at) in the countries where they have gone.” On Megillah 29a, Rabbi Yitzchak says that this “mikdash me’at” refers to synagogues and study halls. Ta-Shema points out that in classic rabbinic literature the concept of the synagogue as a “mini-Temple” usually refers to restrictions–activities one should not do in a synagogue out of respect for its sanctity. The major exception to this is the lighting of a symbolic lamp in replacement of the lamp found in the Temple. In this one way, Jews have for centuries taken Temple practice and brought it into the synagogue.

The earliest explicit reference to this practice is found in a geniza fragment of a midrash published by Levi Ginsberg, “Three sections of the Torah are prefaced by the word tzav [command] because they had been established immediately and for all generations: the sections on lights, … As for the section on lights, whether in the Temple, the synagogues, or the academies, Jews are obligated [to light them ritually] since synagogues and academies are similar to the Temple, as it is written: ‘I will be for them a lesser sanctuary’” [Ezek. 11:16].

Ta-Shema demonstrates that many medieval sources discuss the lighting of a symbolic lamp in the synagogue. For many authorities, these lamps are not simply meant to provide light–they, like the Hannukah candles, are symbols, and as such, some authorities held that it is prohibited to derive benefit from the fire. For instance, the 12th century Sefer Hahasidim writes, “One who lost his coins in the synagogue at night should not take the lamp that is in front of the Ark to look for his coins.” While some of geonim (Babylonian leaders in the 9th-11th centuries) disagreed with this position and do allow for the common use of these lamps, in the popular imagination this lamp was a holy symbol–not just simple lighting for the building.

To return to my original framing of this issue–the technical status versus the popular imagination, the Ner Tamid never quite made its way into the realm of a firm technical obligation. The Shulkhan Arukh (Orah Hayim, 151:9) writes, “It is customary to treat them (synagogues) with honor…and it is customary to light lamps in them in order to honor them.” The Mishnah Berurah (late 19th century) notes that the custom was to light before people came to pray to symbolize the notion that the Shekhinah (God’s presence) arrives before the minyan. Like the Temple lamp which was lit only at night (see Rashi), the Ner Tamid in the synagogue does not seem to have been lit at all times, but mostly at night. Indeed, the Shulkhan Arukh (Orah Hayyim 514:5) refers to lighting the lamp in the synagogue on Yom Tov–clearly these lamps were not always lit. With the advent of electricity, and the adoption of the use of an electric light for the Ner Tamid (primarily due to safety) it is not difficult to leave this lamp on at all times. However, there is no halakhic necessity to do so.