Although the obligation of kindling Shabbos lights rests primarily on the mother, an episode related in Scripture demonstrates that young girls should also participate in this mitzvah. When Rivkah was still unmarried, and but three years old, she kindled the Shabbos lights.
In parshas Chayei Sarah we learn of the first marriage recorded in Scripture -- that of Yitzchak and Rivkah. Avraham, after the death of his wife Sarah, sends his servant Eliezer to his birthplace to find there a wife fitting for his son. Through Divine agency Eliezer ascertains that Rivkah is the destined bride, and brings her back to Yitzchak.
Recording their actual marriage, Scripture states:[1] "Yitzchak brought her into the tent of Sarah his mother, and married her." Rashi, the commentator par excellence on Scripture, comments on the words "the tent of Sarah his mother" that: "He brought her into the tent and behold, she was Sarah his mother. That is to say, she became like his mother Sarah. For as long as Sarah lived there was a light burning [in the tent] from one Shabbos eve to the next; there was always a blessing in the dough; and a cloud was hanging over the tent. Since her death, these had ceased, and when Rivkah came they returned."
Rashi deduces the above from the seeming superfluity of the words "the tent of Sarah his mother." Scripture previously relates that when Avraham’s servant Eliezer brought Rivkah to Yitzchak "the servant told Yitzchak all the things that he had done."[2] Rashi interprets this to mean "He revealed to him the miracles which had been done for him -- that the earth had shrunk for him [enabling him to travel the entire distance to Rivkah’s house in one day], and that Rivkah was ready for him through prayer." After hearing this, Yitzchak then married Rivkah. Scripture should thus simply state "Yitzchak married her."[3] What additional information do we glean from being told that "Yitzchak brought her into the tent of Sarah his mother" -- and only then "he married her"?
Rashi therefore concludes that the words "the tent of Sarah his mother" indicate a reason for Yitzchak’s decision to marry Rivkah. Eliezer, it is true, had already told him of the wonderful miracles involved in choosing Rivkah -- which Eliezer considered a sure sign that "she is the one whom You have selected for Your servant Yitzchak."[4] Nevertheless, Yitzchak was not yet comparable to his mother in piety.[5] Absolute verification was when "He brought her into the tent of Sarah his mother" -- "and behold, she became like Sarah his mother."
Since it was this which determined Yitzchak’s decision that Rivkah was the right one, it follows that he must have seen greater miracles than vouchsafed to Eliezer. They demonstrated unequivocally the utter resemblance of Rivkah to his family in general, and to Sarah in particular.
This, Rashi learns, is alluded to in the words "the tent of Sarah his mother:" Yitzchak saw a miracle connected with "the tent," a miracle in conjunction with "Sarah," and a miracle associated with "his mother."
Let us examine each in order:
In Hebrew, the word "the" in "the tent" is definitive, meaning that the "tent" referred to is known, distinct from all other tents. By comparison with a similar case, we can then deduce how the tent was different from others. When Avraham set out to sacrifice his son Yitzchak, Scripture state
[6] that "Avraham looked up and saw
the place from afar." Rashi explains that Avraham knew it was
the place for the sacrifice because "He saw a cloud hanging over the mountain." Thus, in our case, we know that "
the tent" of Sarah was distinct from all other tents also because "a cloud was hanging over the tent."
We can deduce the miracle associated particularly with Sarah from a prior episode related in Scripture.
[7] When angels came to Avraham in the guise of "guests," he himself took care of all the preparations for receiving them properly -- with one exception: "Avraham hastened to the tent, to Sarah, and said ‘Hurry, three measures of fine flour; knead it and make cakes.’ "
[8] It was specifically Sarah’s task to knead the dough and make bread.
When, therefore, we are told that Yitzchak saw a miracle specially associated with "Sarah," it is understood it was connected with the dough -- "there was always a blessing in the dough."
The miracle associated with "his mother" is that the Shabbos lights remained burning for the whole week, for even a small child knows and sees that it is his
mother who every Shabbos eve kindles the Shabbos lights.
But not all is clear: The order in which Rashi mentions the three miracles is first "there was a light burning from one Shabbos eve to the next," then "there was always a blessing in the dough," and last, "a cloud was hanging over the tent." This is the opposite of the order as alluded to in the verse:[9] First "the tent" -- a cloud hanging, then "Sarah" -- blessing in the dough, and last "his mother" -- a light burning. Moreover, the order as found in Scripture follows more closely the way in which the miracles happened than the way Rashi orders them. The first miracle that would have happened when Rivkah entered the tent would be the appearance of the cloud. Following that would be seen the blessing in the dough when Rivkah worked with it. Finally, the miracle of the Shabbos light burning a full week would be apparent only on the next Shabbos eve.
Yitzchak decided to marry Rivkah only when he knew that she was similar to Sarah his mother. It follows then that Yitzchak was principally interested in the miracles that showed Rivkah to be like his mother in her piety and righteousness. And it is this which causes Rashi to mention the miracles in the order he does. First of all, the miracle that "there was a light burning from one Shabbos eve to the next." Kindling the Shabbos lights is a mitzvah. The miracle that occurred thus emphasized Rivkah’s piety and greatness in performing a mitzvah. The next level is the miracle that "there was always a blessing in the dough." Although this also showed Rivkah’s piety in her actions (kneading the dough), it was not in conjunction with a mitzvah. The miracles of "a cloud hanging over her tent" is not even associated with an action -- and thus does not express Rivkah’s piety as clearly as the previous two.
We can learn a wonderful lesson from the above. Yitzchak married Rivkah only after he saw that her Shabbos lights burnt "from one Shabbos eve to the next," clearly indicating that Rivkah kindled Shabbos lights before her marriage. Moreover, Rashi is of the opinion[10] that Rivkah was three years old when she married, an age when a Jew is not obligated in the observance of mitzvos. Nevertheless, she still fulfilled the mitzvah of Shabbos lights.
Furthermore, even without Rivkah’s lights there would still have been Shabbos lights in the house. Avraham kept the entire Torah, including the Rabbinic commandments;[11] and the halachah requires[12] that if the wife does not kindle Shabbos lights (for whatever reason), the man must do so. We must therefore conclude that after Sarah’s passing, Avraham (and Yitzchak) kindled the Shabbos lights every Shabbos eve. Yet Rivkah, although only three years old then, did not content herself with Avraham’s lighting and lit her own.
This is a clear directive that not only girls of Bas mitzvah age should kindle Shabbos lights,[13] but even younger girls, from three years of age (if they are capable of understanding its meaning), should be brought up and educated in the mitzvah of kindling the Shabbos lights. This applies also when the mother (or others) lights.
As noted above, Avraham himself kindled the Shabbos lights; yet they did not miraculously burn "from one Shabbos eve to the next." This shows the wonderful power in the mitzvah of kindling the Shabbos lights by Jewish daughters, even by a three year old. Every Jewish girl is called a daughter of Sarah, Rivkah, Rachel and Leah, and through her lighting, the whole house is illuminated the entire week.
The difference is that Sarah’s and Rivkah’s lights openly illuminated the house, for the actual light miraculously burned from one Shabbos eve to the next. But in reality, the same thing occurs with everyone who kindles the Shabbos lights. Although we cannot physically see it, every girl who is a daughter of Sarah and Rivkah has the same power -- that the illumination coming from the mitzvah of her Shabbos lighting influences the whole week.
In a deeper sense, "a light burning from one Shabbos eve to the next, blessing always in the dough, and a cloud hanging over the tent," correspond to the three mitzvos given to Jewish women: challah, family purity, and Shabbos lights.[14] Through keeping the mitzvah of Shabbos lights, "the light burns from one Shabbos eve to the next;" through being careful in the mitzvah of challah, "blessing is always in the dough; and through keeping family purity, one merits to have "a cloud hanging over the ten" -- the "cloud" of the Divine Presence.[15]
This gives us a deeper understanding of the order in which Rashi places these three things. He puts them in order of time sequence, corresponding to the three mitzvos from which they derive. As soon as a girl becomes of educable age, she starts kindling the Shabbos lights ("a light burning from one Shabbos eve to the next"). Later, when she is older and starts helping in the house, she works with dough ("blessing always in the dough"). Later still, when she marries, she keeps the mitzvah of family purity ("a cloud hanging over the tent").
Likkutei Sichos, vol. 15, pp. 163-173

Notes:
- (Back to text) Bereishis 24:67
- (Back to text) Bereishis 24:66
- (Back to text) As the Alshich asks: Scripture should state only "He married Rivkah."
- (Back to text) Bereishis 24:14, and see Rashi
- (Back to text) This was the reason Avraham sent Eliezer specifically to his birthplace
- (Back to text) Bereishis 22:4
- (Back to text) Beginning of parshas Vayeira
- (Back to text) Bereishis 18:6
- (Back to text) And also opposite to the order mentioned in Midrash, the source for Rashi’s interpretation of this verse.
- (Back to text) Bereishis 25:20; See also 22:20, Rashi; End of tractate Sofrim
- (Back to text) Bereishis 26:5, Rashi
- (Back to text) Shulchan Aruch Admur HaZakein Orach Chayim, ch. 263, paras. 5,6 and 11
- (Back to text) See Likkutei Sichos vol. 11, p. 281; vol. 17, end of parshas Tazria
- (Back to text) Chizkuni; Gur Arye; Bartenura
- (Back to text) Ibid.