It is now my privilege and honor to present a novel explanation to our royal audience gleaned from a teaching in the Zohar hakadosh. It asserts that lighting the candle represents the light of the holy Shechinah that HKB”H rests on a Jewish home in the merit of the women of the house. Here is a translation of the pertinent passage (Bereishis 50a):
Come and see. When a man is in his home, the mainstay of the home is his wife. For, in her merit, the Shechinah does not leave the home, as we have learned in relation to that which is written (Bereishis 24, 67): “And Yitzchak brought her into the tent of Sarah, his mother,” where a candle burned. For what reason? Because the Shechinah came to the home.
This teaching is based on an elucidation in the Midrash (B.R. 60, 16): For the entire time that Sarah was alive, a lamp burned from the nights of Shabbas to the nights of Shabbas, but when she died, it stopped burning; and when Rivkah came, it (the miraculous, continuous, burning lamp) returned. The Zohar hakadosh explains that the lamp that burned from one Shabbas evening to the next was an indication of the presence of the Shechinah illuminating the home throughout the week.
Elsewhere, we find another related teaching in the Zohar hakadosh (Chayei Sarah 133a): "ויביאה יצחק האהלה שרה אמו" (“And Yitzchak brought her into the tent of Sarah, his mother”). Rabbi Yossi said: This passuk is difficult. Instead of "האהלה", it should have simply said אהל שרה אמו"". Why does it say "האהלה"? It is because the Shechinah returned there. For, as long as Sarah was alive, the Shechinah did not leave her, and the lamp burned from erev Shabbas to erev Shabbas and would provide illumination for all the days of that week. After she died, the lamp was extinguished. But when Rivkah came, the Shechinah returned and the lamp was rekindled. The words “Sarah, his mother” indicate that she (Rivkah) resembled Sarah in all her deeds.
I believe we can interpret this passage in the Zohar based on another statement in the Zohar hakadosh (Pinchas 231b) related to the passuk (Mishlei 20, 27): "נר ה' נשמת אדם"—a man’s neshamah is the lamp of Hashem; this is the holy Shechinah. In the gloss of Rabeinu Chaim Vital on the Zohar (9), he writes: The Shechinah is called the “lamp of Hashem”; she is the neshamah of Yisrael that is called man (“adam”). This is the gist of what the author of the Tanya wrote in Likutei Amarim (Chapter 41). He teaches that the name “Shechinah” indicates that she dwells (“shochenet”) and clothes herself within all the worlds to provide them with life and sustain them.
Thus, we learn the significance of the fact that Sarah Imeinu and Rivkah Imeinu lit a lamp in honor of Shabbas that burned from one erev Shabbas to the next. This indicated that on account of their incredible kedushah, the presence of the Shechinah was drawn into their home and remained there for the entire week. This phenomenon recurred every erev Shabbas with the kindling of the lamp.
