According to an ancient midrash (rabbinic interpretation of the Torah), all the time that Sarah lived, a sense of holiness was palpably present in her home. The food she made tasted of blessing; a cloud hovered at the doorways of her tent - which were always spread wide to receive guests - and a candle burned without ceasing from one Shabbat to the next.
When Sarah died, as reported at the beginning of this past week's parsha (Gen 23:1-2), these indications of divine presence departed.
But when Rebekah joined the family, the midrash tells us that these signs returned. (Genesis Rabbah 60:16). This, say the rabbis, is what is hinted at in the verse we read towards the end of this Shabbat's parsha: "And Isaac brought her into the tent of Sarah his mother, and made Rebekah his wife, and he loved her; thus was Isaac comforted after [the loss of] his mother." (Gen 24:16)
A light once again burned from one Shabbat to the next.