Shabbat 016

1:
The sages wanted Shabbat to be a day of delight, a day of happiness and joy. However, as we learned in Shabbat 009, kindling a fire is one of the thirty nine melakhot [primary tasks] which we may not perform on Shabbat. Thus there is a dilemma: Shabbat eve spent in darkness can hardly be a day of delight, happiness and joy, but the light may not be lit on Shabbat. The answer is, of course, that lights must be lit before Shabbat begins, so that they will continue to shed their light throughout the evening. (The Karaïtes, who rejected the 'Unwritten Torah', forbad any light or heat in their homes on the Sabbath day! Thus the rabbinic idea of permitting something that was started before Shabbat begins and thereafter continues automatically was a definite liberalization. See Shabbat 010. While it is forbidden to light a light there is nothing to prevent us having a light burning during Shabbat.)

2:
It is not the Written Torah which requires us to have lights in our homes on the Sabbath eve; this requirement is one of seven innovations of the sages. That is to say, in seven instances the sages require us to do something as if it were a mitzvah of the Torah when, in fact, it is not. The Seven Mitzvot of the Sages are:

Lighting lights (candles) in honour of Shabbat (and YomTov);
Lighting lights on Ĥanukah;
Reading the Megillah on Purim;
Reciting Hallel on festive days;
Washing the hands before eating bread;
Reciting a berakhah before enjoying the good things of this world;
The institution of the Eruv.

In all these cases we recite a berakhah before performing these religious tasks, just as we do when performing a mitzvah that is written in the Torah. (We shall expatiate on this when we reach paragraph 5 of this Section.)

3:
This is the reason why the poskim [decisors] are very careful in the way they word the requirement to light the Shabbat candles. This is how Rambam words this requirement [Mishneh Torah, Hilkhot Shabbat 5:1]

One can feel here the extremely careful - almost tortuous - wording of this master of wording: lighting the candles is a requirement not a permission; but nevertheless it is not a commandment; therefore we must "have a light burning" in our homes.

4:
The word used in this connection by Rambam and all the other poskim is Ner in Hebrew. Nowadays this is usually translated "candle", but such a translation tends to obscure the real purpose of the lights. The lighting of the Shabbat lights was originally prompted by a utilitarian consideration; it was only afterwards that it became imbued with the spiritual and emotional meaning that it has for so many people today. We think of the Shabbat lights in terms of candles twinkling on the Sabbath table (or near it). But a picture from a few centuries ago will amply illustrate that then the Sabbath lights were a kind of chandelier hanging over the dining table. The chandelier was attached to a rope and pulley; the housewife would lower the chandelier in order to light the lights and then raise it up again above the table.

5:
For centuries, obviously, the Shabbat lights were fueled by oil - as is also the case in the Italian wood carving above, which was made 400 years ago. Each cruse of oil would have one or more wicks feeding from it - the more wicks the more light. (In the above illustration the bowl underneath the branches of the chandelier is the fuel reservoir.) Strictly speaking, one need only light one wick in order to fulfill the requirement of the sages - and that, presumably, is all that the poorest of the poor could permit themselves.

6:
However, it gradually became the custom to light a minimum of two lights. In the Torah there are two recensions of the Ten Commandments: the original recension is in the book of Exodus; but when Moses recapitualtes the laws in the book of Deuteronomy he repeats many of them. In the case of the commandment concerning Shabbat [Exodus 20:8-11 and Deuteronomy 5:12-15] there are several clear variations between the two recensions. The variation that concerns us here is in the very first word: the Exodus version requires us to "remember the Sabbath day to sanctify it" whereas the version in Deuteronomy exhorts us to "observe the Sabbath day to sanctify it". The traditional reconciliation of this divergence is that at Sinai Israel heard both words uttered by the Divine Voice simultaneously. (This is alluded to in the second verse of Alkabetz' famous hymn Lekha Dodi which is sung in the synagogue on Friday evening. See Shabbat 015.) Thus it came about that the custom was to light two lights, "one for 'remember' and one for 'observe'", as Rabbi Karo points out in paragraph 1 of Section 263 (above).

7:
However, while the custom is to light at least two lights (because on weekdays the less well-off would usually make do with just one) there is no reason why one should not light more than two. For example, many have the custom to light one light for each member of the family, starting off with just two and then adding a light as each child is born. However, one must maintain those extra lights thereafter, having always the same number of multiple lights, or a greater number, but never less. The last sentence in Rabbi Isserles' note simply means that having more lights than two does not detract from the fact that two of them represent 'remember' and 'observe'.

8:
Rabbi Moshe Isserles also states in his note that if one was derelict in lighting the Sabbath lights on one occasion this must be recompensed by an additional light on every Shabbat thereafter.

9:
Obviously, the quality of the light that would be generated would depend on the quality of the oil and the wicks used. The second chapter of Tractate Shabbat in the Mishnah is devoted to a list of fuels and wicks that should be avoided because they would produce a wavering light or generate too much smoke and the like. (In many congregations it is still the custom to 'learn' this chapter of Mishnah in the synagogue on Friday night as part of the service - Bameh Madlikin. Obviously, originally it was a very practical innovation.)

10:
Thus in the first paragraph of Section 263 (above) Rabbi Karo reminds us that "one should be careful to make a nice light". The quality of the oil and the wicks is important; now that candles have almost universally replaced oil lamps one should choose a good quality candle that will give a steady light and burn at the very least until after the Sabbath meal. (In order not to over-burden the shiur I shall only relate to the possibility of using a light source other than candles in response to specific questions - which are invited.)