With what may one light the Shabbat lamp, and with what may one not light it? With regard to types of prohibited wicks, one may light neither with cedar bast [lekhesh], nor with uncombed flax [ḥosen], nor with raw silk [kalakh], nor with willow bast [petilat ha’idan], nor with desert weed [petilat hamidbar], nor with green moss that is on the surface of the water. With regard to types of prohibited oils, one may light neither with pitch [zefet], nor with wax [sha’ava], nor with castor oil [shemen kik], nor with burnt oil [shemen sereifa], nor with fat from a sheep’s tail [alya], nor with tallow [ḥelev]. Naḥum the Mede says: One may light with boiled tallow. And the Rabbis say: Both tallow that was boiled and tallow that was not boiled, one may not light with them.
(ה) מְסַדֵּר אָדָם שֻׁלְחָנוֹ בְּעֶרֶב שַׁבָּת וְאַף עַל פִּי שֶׁאֵינוֹ צָרִיךְ אֶלָּא לִכְזַיִת. וְכֵן מְסַדֵּר שֻׁלְחָנוֹ בְּמוֹצָאֵי שַׁבָּת וְאַף עַל פִּי שֶׁאֵינוֹ צָרִיךְ אֶלָּא לִכְזַיִת. כְּדֵי לְכַבְּדוֹ בִּכְנִיסָתוֹ וּבִיצִיאָתוֹ. וְצָרִיךְ לְתַקֵּן בֵּיתוֹ מִבְּעוֹד יוֹם מִפְּנֵי כְּבוֹד הַשַּׁבָּת. וְיִהְיֶה נֵר דָּלוּק וְשֻׁלְחָן עָרוּךְ לֶאֱכל וּמִטָּה מֻצַּעַת שֶׁכָּל אֵלּוּ לִכְבוֹד שַׁבָּת הֵן:
(5) One should spread his Sabbath table on Friday, even if he requires no more than an olive's bulk of food; so too, he should set his table at the end of the Sabbath, even if he requires only a minute amount of food, in order to honor the Sabbath both at its entrance and departure. One should also set the house in order on Friday before sunset in honor of the Sabbath. A lamp should be lit, a table spread, and a bed properly arranged. All these are marks of respect for the Sabbath.
תוספות שבת כה: ד”ה הדלקת
…דחובה היא שיסעוד במקום הנר משום עונג
Tosafot Shabbat 25b s.v. hadlakat
…For it is an obligation to dine in proximity to the candle, because of oneg [Shabbbat].
מהר”ל חידושי אגדות שבת כג:
…כי נר של שבת דבר מצוה הוא, וכאילו הוא נר ה’ ולכך דומה במעלתו אל עמוד אש שהיה מן הש”י [=השם יתברך]. ואינו כמו שאר נר בחול, רק זה דבר קדושה…
Maharal Chiddushei Aggadot Shabbat 23b
…For the Shabbat candle is a matter of mitzva, and it is as though it is the candle of God, and therefore it is similar in its quality to the pillar of fire, which was from God. And it is not like other candles of the weekday, rather this is a sacred thing…
ראבי”ה א שבת קצט
ונראה לי דנהגו בשתי נרות, שאחת היא לאכול לאורה ואין היכר כי אם בשתים…ותו יש לומר חד כנגד זכור וחד כנגד שמור, כדאמרינן <בפרק במה מדליקין> חזו ההוא סבא דהוה נקיט תרי מדאני דאסא וכו’ ות[יסגי] לך בחד חד כנגד זכור וחד כנגד שמור…ולפי זה אין להוסיף נר שלישי, ואם צריך לו ירחיקנו להכירא…
Ra'aviyah I Shabbat 199
It seems to me that they adopted the custom of two candles, for one is to eat by its light, and it is recognizable [that the lighting is for Shabbat] only with two…Furthermore, one can say that one corresponds to “zachor” (remember) and one corresponds to “shamor” (keep), as we say “They saw that old man who took two bunches of myrtle…’Wouldn’t one suffice for you?’ ‘One corresponding to zachor and one corresponding to shamor. ‘” (Shabbat 33b)… According to this, one should not add a third candle, and if one needs it, he should place it at a distance so that it is recognizable…
(א) הַדְלָ [קַ] ת נֵר בְּשַׁבָּת אֵינָהּ רְשׁוּת אִם רָצָה מַדְלִיק וְאִם רָצָה אֵינוֹ מַדְלִיק. וְלֹא מִצְוָה שֶׁאֵינוֹ חַיָּב לִרְדֹּף אַחֲרֶיהָ עַד שֶׁיַּעֲשֶׂנָה כְּגוֹן עֵרוּבֵי חֲצֵרוֹת אוֹ נְטִילַת יָדַיִם לַאֲכִילָה אֶלָּא זֶה חוֹבָה. וְאֶחָד אֲנָשִׁים וְאֶחָד נָשִׁים חַיָּבִין לִהְיוֹת בְּבָתֵּיהֶן נֵר דָּלוּק בְּשַׁבָּת. אֲפִלּוּ אֵין לוֹ מַה יֹּאכַל שׁוֹאֵל עַל הַפְּתָחִים וְלוֹקֵחַ שֶׁמֶן וּמַדְלִיק אֶת הַנֵּר שֶׁזֶּה בִּכְלַל עֹנֶג שַׁבָּת. וְחַיָּב לְבָרֵךְ קֹדֶם הַדְלָקָה בָּרוּךְ אַתָּה ה' אֱלֹקֵינוּ מֶלֶךְ הָעוֹלָם אֲשֶׁר קִדְּשָׁנוּ בְּמִצְוֹתָיו וְצִוָּנוּ לְהַדְלִיק נֵר שֶׁל שַׁבָּת. כְּדֶרֶךְ שֶׁמְּבָרֵךְ עַל כָּל הַדְּבָרִים שֶׁהוּא חַיָּב בָּהֶם מִדִּבְרֵי סוֹפְרִים:
(1) The lighting of Sabbath lights is not of free choice, to light or not to light as one chooses, nor is it the kind of religious performance that an individual is not called upon to make a special effort to render, such as preparing an eruv in courtyards or washing the hands before eating. It is rather a duty, binding on men and women alike; they are obligated to have lamps burning in their homes on Sabbath eve. Even if one has nothing to eat, let him go begging at the doors, buy oil, and light a lamp, forming an integral part of Sabbath delight (oneg shabbath). Before lighting, one should recite a blessing: "Blessed art thou, Lord our God, King of the universe, who hast sanctified us with thy commandments, and commanded us to light the Sabbath lights." This is on the same principle that one recites a benediction over all duties introduced by the sages.
שו”ת מהרי”ל נג
…ב’ וג’ בעלי בתים אוכלים במקום אחד, כל אחד מברך על מנורה שלו, אף על פי שיש כבר אורה מרובה…ובעניות דעתי נ”ל [=נראה לי] ליישב דכל מה דמיתוסף אורה יש ביה שלום בית טפי ושמחה יתירה להנאת אורה בכל זויות וזויות…
Responsa Maharil 53
…Two or three heads of household eat in one place, each one recites a beracha on his own lamp, even though there is already a great amount of light. And in my humble opinion it seems to me to [make this view] sit well, that anything that adds light has more shalom bayit and extra rejoicing by enjoying the light in each and every corner…
הרבי מליובאוויטש “הנר משפיע” את עלית (משיחת מוצ”ש פרשת בראשית תשל”ה), עמ’ 135
הנה בימינו אלה, יש להשתדל שכל בת ישראל תדליק בעצמה נר ובברכה, ועד לילדות רכות בשנים שהגיעו לגיל חינוך, ואפשר להסביר להן את ענינה הדלקת נר שבת, בהוספת הביאור—שזוהי שליחות מהקב”ה, והוא בעצמו נותן כחות לילדה קטנה זו, שעל ידי זה שתדליק נר בפמוט שלה, תכניס אורה ותביא להשראת השכינה—יהדות ואלקות—בבית.
Rav Menachem Mendel Schneerson, 'The Light that Influences' At Alit (From a sicha following Shabbat Bereishit 1975), p. 135
Behold in these days, one should make an effort that every daughter of Israel light a candle for herself with a beracha, including young girls who have reached the age of educability. And it is possible to explain to them the matter of lighting the Shabbat candle, with the additional explanation that this is a mission from God, and He Himself gives strength to this little girl, that through her lighting a candle in her candlestick, she brings in light and leads to the dwelling of the Shechina—Judaism and Godliness—in the home.
שולחן ערוך או”ח רסג: י
לבה”ג, כיון שהדליק נר של שבת חל עליו שבת ונאסר במלאכה. ועל פי זה נוהגות קצת נשים שאחר שברכו והדליקו הנרות משליכות לארץ הפתילה שבידן שהדליקו בה, ואין מכבות אותה…ויש חולקים על בעל ה”ג [=הלכות גדולות] ואומרים שאין קבלת שבת תלוי בהדלקת הנר אלא בתפלת ערבית…הגה: והמנהג שאותה אשה המדלקת מקבלת שבת בהדלקה, אם לא שהתנה תחלה, ואפילו תנאי בלב סגי (מרדכי); אבל שאר בני הבית מותרין במלאכה עד ברכו.
Shulchan Aruch OC 263:10
For Behag, since he lit the Shabbat candles, Shabbat has taken effect for him and he is prohibited from labor. And according to this, a few women have the practice that after they have recited the beracha and lit candles, they cast to the ground the wick in their hand with which they lit, and do not extinguish it…And there are those who disagree with Behag and say that accepting Shabbat is not dependent on lighting the candle, but rather on the ma’ariv prayer…Rema: And the custom is that the woman who lights accepts Shabbat through her lighting, if she did not make a condition first, and even a mental condition suffices, but the rest of the household members are permitted in [performing] labor until barechu.
רבנו יונה, אגרת התשובה יום ז כלל א
האשה כשמדלקת את הנר בערב שבת תזהר בנפשה שתתפלל באותה שעה על בניה שיהיו מצליחים בתורה ובמצות וביראת שמים, מפני שתפלה זו נאה להתפלל בשעה שהאירה נר של שבת כענין שנאמר כי נר מצוה ותורה אור.
Rabbeinu Yona Iggeret Ha-teshuva Day 7 Rule 1
A woman when she lights the candle on Erev Shabbat should take care to pray at that time over her children that they be successful in Torah and in mitzvot and in awe of Heaven, since this prayer is fitting to pray at a time when she has illuminated the candle of Shabbat, as the matter as is said “for a candle is a mitzva and Torah is light.” (Mishlei 6:23)
The mitzva to light candles applies to all Jews, men and women, single and married, since everyone is obligated to honor and enjoy Shabbat. However, within the family the wife takes precedence for this mitzva, because she is the ba’alat ha-bayit (mistress of the household) and responsible for running it. Therefore she has the privilege of fulfilling this mitzva, which is designed to ensure peace in the home. She exempts all other members of her household with her lighting. But if the wife is running late and it is getting close to shki’a, it is better that her husband or one of the children light the candles so that she does not risk desecrating Shabbat by lighting the candles herself (SA 263:2; MB 262:11).
The precedence of women over men with regard to candle lighting indicates that shalom bayit is primarily dependent on women, and the light of Torah and faith permeates the home due to the wife. Through her special inner awareness she knows how to illuminate the path of faith for her husband and children, and she directs them toward diligent Torah study. This accords with the words of the Sages: “The promise [of future reward] for women is greater than that of men,” because they send their children to study Torah in school, encourage their husbands to study long hours in the beit midrash, and wait for them to come home (Berakhot 17a). Nevertheless, when the wife is unable to light the candles, the husband should do so, for when necessary he too can bring peace to the home and introduce an atmosphere of faith and Torah to it.
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The law requires that only one candle be lit, thus providing light in the home. However the custom is to light two candles, one corresponding to Zakhor and the other to Shamor. Some women customarily light one candle for each member of the household; others light seven candles, corresponding to the seven days of the week; still others light ten, corresponding to the Ten Commandments. All these customs apply when a woman is in her own home, but if she is a visitor in someone else’s home, the custom is that she lights just two candles (SSK 43:3).