A. Two Versions of the Ten Commandments
The Ten Commandments are written twice in the Torah, in Exodus and Deuteronomy. Surprisingly, there are differences between them. For example, the reason for observing Shabbat given in Exodus is because G-d rested on the seventh day, while in Deuteronomy it is to remember the Exodus from Egypt (Source 1). How is this possible? (Source 2).
The commentaries explain that the differences are rooted in the fact that Deuteronomy was spoken freely by Moses in his own style (Source 3).
Interestingly, the kiddush we recite on Friday night contains both reasons—G-d’s rest on the seventh day and a remembrance for the Exodus from Egypt (Source 4).
B. Different Recognitions
G-d controls the world in two ways: Within nature, revealing how the laws of nature are G-dly; and supernaturally, revealing G-d’s infinite power.
We are commanded to observe the Shabbat to train us to recognize both of these elements. When we observe the Sabbath because G-d created the world in six days and rested on Shabbat, we reinforce our faith that nature was created and is controlled by G-d. When we observe Shabbat to recall the Exodus, we reinforce our belief that we can always pray for a miracle beyond nature.
C. Illuminating the Home
Women were given the special mitzvah of lighting Shabbat candles, brightening their homes. Just like Sarah’s candles miraculously burned for the entire week (Source 5), so too, every woman has the power to brighten and warm their home the whole week, not just on Shabbat