Shabbat 018

1:
The Gemara [Shabbat 23b] relates the following:

The Israelites in their desert wanderings were accompanied by two divine manifestations: a pillar of cloud by day and a pillar of fire by night. According to the manner in which the baraita which Rav Yosef quotes to his wife interprets the biblical passage the pillar of cloud did not depart by day, but when the pillar of fire arrived it waited a while before disappearing; and the same happened when the time came for the pillar of fire to give place to the pillar of cloud. This, he intimated, suggested also the the Shabbat candles should not be lit when it is so late in the day that darkness is coming on apace, for the lights of Shabbat should also 'complement' the daytime that precedes Shabbat. Rav Yosef's wife obviously decided to go to the opposite extreme and light the Shabbat candles very early on, while it was still clearly Friday afternoon. An old (and anonymous) sage told her that there was also a baraita which required the Shabbat candles to be lit "neither too early not too late".

2:
This, of course, does not help us today very much in defining a good time to light the Shabbat candles. The best I can do is to repeat what I wrote in Shabbat 013 about this matter:

Rabbi Israel Meir Kagan, the celebrated author of the commentary "Mishnah Berurah", asserts that this is the optimal time for lighting the Shabbat candles: "half an hour or at least a third of an hour before sunset".

3:
The reason for this regulation may not at first seem clear to us. This is because we are accustomed to view the lighting of the Shabbat candles as a religious ritual. But I have already explained (in Shabbat 016) that the original purpose of the Shabbat candles was to ensure that the Sabbath meal would be enjoyed with lights burning. (In earlier times the poor would eat their evening meal before dark in order to save the cost of artificial lighting. The sages wished to ensure that the Sabbath evening meal would be eaten on Shabbat, after dark, and so they enacted that every Jew, even the poorest who must go begging to raise the cost, must have lights burning in their home on Friday night, as this is part of Oneg Shabbat, the pleasure of Shabbat [see Shabbat 017].) If these candles (fulfilling the same function as do our electric lights today) are lit too early in the day it will not be obvious that they are being lit in honour of Shabbat.

4:
The second part of paragraph 4 of Section 263, however, recognizes that sometimes it is necessary to light the Shabbat candles quite some time before sunset – much more than just 18 or 30 minutes before. On several occasions we have pointed out that during the summer this is the case nowadays in most western congregations because the institution of daylight saving makes Shabbat begin at a very late hour (the lateness depending on how far north or south of the equator one lives). Plag ha-Minĥah is seen as being the very earliest time on Friday afternoon that the Shabbat candles may be lit, and, of course, from that moment it is Shabbat for all purposes and nothing may be done thereafter that may not be done on Shabbat. (In Shabbat 013, explanation 6 I gave a brief explanation of the time of Plag ha-Minĥah.)

5:
I have omitted the note which Rabbi Moshe Isserles adds at the end of Paragraph 4 of Section 263, as not really being relevant to our situation today.

Nehama Barbiru writes:

Following the now hypothetical situation of not having money to buy both oil and wine etc., I have a question. If someone is cut off from society e.g. kidnapped, and does not know what day it is (was unconscious), how does he observe the Shabbat?

I respond:

In the Torah [Numbers 15:32] there is a story that takes place during the desert wandering: a man was caught gathering wood on Shabbat. The story itself does not concern us here, but the fact that the Torah seems to emphasize that the incident took place in the desert does concern us here. In his commentary on that passage Rabbenu Beĥayyé makes the following comment: