(1) Moses then convoked the whole Israelite community and said to them: These are the things that the Lord has commanded you to do:
(2) On six days work may be done, but on the seventh day you shall have a Sabbath of complete rest, holy to the Lord; whoever does any work on it shall be put to death.
(3) You shall kindle no fire throughout your settlements on the Sabbath day.
(1) Moses then convoked: Moses convened the people immediately after he had descended the second time from Mount Sinai, that is, on the eleventh of Tishri.
The whole Israelite community: The construction of the Temple is a communal undertaking, but it concerns each of the Children of Israel personally. Thus, not only the lines of Moses and Aaron are united, but of the entire nation as well.
(2) On six days work may be done, but on the seventh day you shall have a Sabbath of complete rest, holy to the Lord: Earlier, on Mount Sinai, the commandment to refrain from construction on Shabbat was given at the very end of the description of the Tabernacle (“Speak to the Israelite people and say: Nevertheless, you must keep My Sabbaths,” 31:13). But here Moses actually begins with that. In the domain of ideas, restrictive conditions need be mentioned only at the end. But where actual practice is concerned, those restrictions come first.
A Sabbath of complete rest, holy to the Lord: The practical Sabbath prohibitions encountered in the Torah heretofore concerned the collection of the manna, primarily (16:11 ff.). But now that the people are moving to the construction of the Tabernacle, their Shabbat observance must be supplemented with new aspects.
Whoever does any work on it shall be put to death: Practically speaking, a Jewish court cannot sentence a person to death for violating the Sabbath. But the idea that violating the Sabbath entails death, at least in principle, is especially important.
The world is designed such that any constant movement, whether in the material or spiritual human realms, must be periodically suspended with pauses. Any movement that is perfectly continuous leads to death. And in this sense, a person who is constantly at work without a day of rest will die.
Moreover, a person who gets carried away by something of great importance, especially in the spiritual and religious realms, is inclined to keep moving ever forward without looking back. But unless you stop from time to time to look around, and to take stock of your progress, you are in danger of going off in the wrong direction. The weekly hiatus that the Shabbat provides is needed in order to prevent that.
(3) You shall kindle no fire throughout your settlements on the Sabbath day: The essence of Shabbat is to “suspend transformation of the world.” And fire is the most powerful instrument for transforming the world that humans have. This is why igniting and using fire is emphasized so prominently among all the Shabbat prohibitions.
You shall kindle no fire: The Karaites (a Jewish sect that professed, in its religious observances and opinions, to follow the Bible to the exclusion of rabbinical traditions and laws) interpreted the words lo teva’aru esh, as “You shall allow no fire to burn” on the Sabbath. That is, not even fire that was kindled before the Sabbath began, and was left to burn on its own.
In contrast, Rabbinic tradition understands lo teva’aru as a prohibition of actually kindling fire on Shabbat, whereas fire that was kindled before Shabbat may continue to burn on its own on Shabbat, in order to provide heat or light. We emphasize this idea by lighting the Shabbat candles every Friday afternoon (in winter) or evening (in summer), always shortly before sunset, which marks the onset of Shabbat.