1) It is obviously impossible for us to determine the exact moment that Friday ends and Shabbat begins. According to most authorities, once the sun sets (Shkiah), we enter a period of time in which we are uncertain as to whether or not it is ''day'' or ''night.'' This period is called ''Bein Hashemashot,'' and it is forbidden during this time of uncertainty to perform Melacha (Torah-prohibited labor) as well as most Rabbinically prohibited acts (certain Rabbinically prohibited acts may be performed in pressing circumstances or for the sake of a Mitzvah). However, some authorities rule that we don't enter the period of uncertainty until sometime after the sun has set, and its clear that, in this Halacha, the Kitzur Shulchan Aruch concurs with these authorities, and therefore sets candle-lighting time at a half an hour before nightfall, rather than a similar period before sunset. According to all authorities, the appearance of three medium-sized stars signals the beginning of the ''night.'' According to the authorities who rule that the period of uncertainty begins at sunset, it should be permissible to light Shabbat candles until a moment before sunset. However, the custom in most communities is to light-candles and begin Shabbat about 18 minutes before sunset; there are two possible reasons for this practice. Firstly, most authorities rule that it is a Mitzvah (derived from the Torah) to begin Shabbat while it is still definitely ''daytime,'' i.e. before sunset. This concept is called ''Mosif Mechol Al HaKodesh'' (lit: ''adding part of the non-holy to the holy,'' in other words, adding part of the weekday to Shabbat ). Secondly, even those authorities who rule that it is not an actual Mitzvah to begin Shabbat early, still rule that everyone should refrain from performing prohibited acts a short time before sunset, because if one got into the habit of waiting until a moment before sunset to begin Shabbat, one could easily end up performing a prohibited act after sunset (See Shulchan Aruch 261 and commentaries). 2) According to the Mishna Berura (261:30), when the congregation in the synagogue sing the words ''Welcome Bride'' in the song ''Lecha Dodi,'' they are accepting Shabbat upon themselves, and prohibited activities may not be performed by any member of the congregation (even those not in Synagogue), from that point onwards. 3) Psalm 92. 4) It is permissible to begin Shabbat anytime after ''Plag HaMincha'' on Friday afternoon, which is always one and a quarter Halachic hours before sunset (a Halachic ''hour'' is equal to one twelfth of the time from sunrise to sunset (some say from dawn to dark) ) (See Rema 261:2).

1) Corresponding to the Ten Commandments (Shelah). 2) Corresponding to the days of the week (Magen Avraham). 3) ''Remember the Day of Shabbat'' (Exodus 20:8) and ''Keep the Day of Shabbat'' (Deut 5:12). 4) Tractate Shabbat 23b. 5) Proverbs 6:23. 6) Since the mitzvah to light Shabbat candles is related to child-bearing, many women have the custom to light a Shabbat candle for each child. 7) I Samuel 1, 2:1-10 - which relates Chana's prayer for a son.

מצוה להרבות בנרות לכבוד שבת יש נוהגין להדליק עשרה ויש מדליקין שבעה ועל כל פנים ראוי שלא לפחות משתי נרות נגד זכור ושמור ואך בשעת הדחק גם בחד סגי ויהיו ארוכים שידלקו לכל הפחות עד לאחר האכילה ויהדר לקנות נרות יפים דאמר רב הונא הרגיל בנר שבת להשתדל בו לעשותו יפה הויין לו בנים תלמידי חכמים שנאמר כי נר מצוה ותורה אור על ידי נר מצוה בא אור תורה ולכן ראוי שתתפלל האשה בשעת הדלקה שיתן לה הקדוש ברוך הוא בנים זכרים מאירים בתורה וטוב שתתן מקודם איזה פרוטות לצדקה ואשה קשת רוח בגידול בנים או שאין לה כלל סגולה שתאמר לאחר הדלקת הנרות ההפטרה של יום ראשון דראש השנה וטוב שתבין מה שהיא אומרת ותאמר בכוונה

1) The Mishna Berurah (264:23) states that the reason olive oil was preferred is because it is drawn up the wick better than all other oils; he raises the possibility that since some modern substances light just as well as olive oil, and sometimes even better, there may be no reason to choose olive oil over anything else. However, the Midrash Tanchuma (B'Ha'aloscha) states:"...we find that G-d desires olive oil more than all other oils..." (because He chose it as the oil which must be used in the golden Menorah in the Beit Hamikdash (Temple) ). 2) They are unacceptable either because they are not drawn up the wick properly, creating a sputtering, unstable flame, which one might come to adjust on Shabbat. Some are unacceptable because they have a bad odor, which is not only a degradation of Shabbat, but also makes it difficult to eat near the candles. 3) Any wick that causes sputtering is not acceptable, because one may come to adjust the flame on Shabbat, thereby violating the prohibition against igniting a fire on Shabbat. 4) The author, Rabbi Shlomo Ganzfried, lived in Ungvar, Hungary. 5) Tallow doesn't have to be kosher, but it should be made of fat that comes from kosher animals. 6) Using tallow like one would use oil is forbidden because, in that form, it is not drawn well into the wick.