What exactly are the commands of Shabbat? To whom do they apply?
(א) וַיְכֻלּ֛וּ הַשָּׁמַ֥יִם וְהָאָ֖רֶץ וְכָל־צְבָאָֽם׃ (ב) וַיְכַ֤ל אֱלֹהִים֙ בַּיּ֣וֹם הַשְּׁבִיעִ֔י מְלַאכְתּ֖וֹ אֲשֶׁ֣ר עָשָׂ֑ה וַיִּשְׁבֹּת֙ בַּיּ֣וֹם הַשְּׁבִיעִ֔י מִכָּל־מְלַאכְתּ֖וֹ אֲשֶׁ֥ר עָשָֽׂה׃ (ג) וַיְבָ֤רֶךְ אֱלֹהִים֙ אֶת־י֣וֹם הַשְּׁבִיעִ֔י וַיְקַדֵּ֖שׁ אֹת֑וֹ כִּ֣י ב֤וֹ שָׁבַת֙ מִכָּל־מְלַאכְתּ֔וֹ אֲשֶׁר־בָּרָ֥א אֱלֹהִ֖ים לַעֲשֽׂוֹת׃
(1) The heaven and the earth were finished, and all their array. (2) On the seventh day God finished the work that God did, and God ceased on the seventh day from all the work that God had done. (3) And God blessed the seventh day and declared it holy, because on it God ceased from all the work of creation that God had done.
(16) The Israelite people shall keep the sabbath, observing the sabbath throughout the ages as a covenant for all time: (17) it shall be a sign for all time between Me and the people of Israel. For in six days the LORD made heaven and earth, and on the seventh day God ceased from work and was refreshed.
(יב) שָׁמ֣֛וֹר אֶת־י֥וֹם֩ הַשַׁבָּ֖֨ת לְקַדְּשׁ֑֜וֹ כַּאֲשֶׁ֥ר צִוְּךָ֖֣ ׀ יְהוָ֥֣ה אֱלֹהֶֽ֗יךָ (יג) שֵׁ֤֣שֶׁת יָמִ֣ים֙ תַּֽעֲבֹ֔ד֮ וְעָשִׂ֖֣יתָ כָּֿל־מְלַאכְתֶּֽךָ֒׃ (יד) וְי֙וֹם֙ הַשְּׁבִיעִ֜֔י שַׁבָּ֖֣ת ׀ לַיהוָ֖֣ה אֱלֹהֶ֑֗יךָ לֹ֣א תַעֲשֶׂ֣ה כָל־מְלָאכָ֡ה אַתָּ֣ה וּבִנְךָֽ־וּבִתֶּ֣ךָ וְעַבְדְּךָֽ־וַ֠אֲמָתֶךָ וְשׁוֹרְךָ֨ וַחֲמֹֽרְךָ֜ וְכָל־בְּהֶמְתֶּ֗ךָ וְגֵֽרְךָ֙ אֲשֶׁ֣ר בִּשְׁעָרֶ֔יךָ לְמַ֗עַן יָנ֛וּחַ עַבְדְּךָ֥ וַאֲמָתְךָ֖ כָּמֽ֑וֹךָ׃ (טו) וְזָכַרְתָּ֞֗ כִּ֣י־עֶ֤֥בֶד הָיִ֣֙יתָ֙ ׀ בְּאֶ֣רֶץ מִצְרַ֔֗יִם וַיֹּצִ֨אֲךָ֜֩ יְהוָ֤֨ה אֱלֹהֶ֤֙יךָ֙ מִשָּׁ֔ם֙ בְּיָ֤֥ד חֲזָקָ֖ה֙ וּבִזְרֹ֣עַ נְטוּיָ֑֔ה עַל־כֵּ֗ן צִוְּךָ֙ יְהוָ֣ה אֱלֹהֶ֔יךָ לַעֲשׂ֖וֹת אֶת־י֥וֹם הַשַׁבָּֽת׃ (ס)
12 Guard the sabbath day, to keep it holy, as the Lord your God commanded you. 13 Six days shall you labor and do all your melakhah; 14 but the seventh day is a sabbath for the Lord your God; do not do any manner of melakhah on it, not you, your son, your daughter, your male or female servant, your ox, your donkey, any of your animals nor the stranger within your gates; so that your male and female servants can rest just like you. 15 And so that you will be mindful that you were a slave in the land of Egypt, and the Lord your God took you out of there with a mighty hand and an outstretched arm; therefore the Lord your God commanded you to perform the sabbath day. (translation from Ethan Tucker)
שבת וינפש / Shavat Vayinafash
Rest and re-ensoulment
The Sabbath, Rabbi Abraham Joshua Heschel
...The Sabbath is the most precious present mankind has received from the treasure house of God. All week we think: The spirit is too far away, and we succumb to spiritual absenteeism, or at best we pray: Send us a little of Thy spirit. On the Sabbath the spirit stands and pleads: Accept all excellence from me...
To set apart one day a week for freedom, a day on which we would not use the instruments which have been so easily tuned into weapons of destruction, a day for being with ourselves, a day of detachment from the vulgar, of independence of external obligations, a day on which we stop worshipping the idols of technical civilization, a day on which we use no money, a day of armistice in the economic struggle with our fellow men and the forces of nature – is there any institution that holds out a great hope for man's progress than the Sabbath?
[Heschel, A.J. The Sabbath. Canada: Harper Collins Publishers Canada Ltd., 1979, pp.18, 28.]
"Powering Down" by Jennifer Bleyer, Tablet Magazine
Shabbat is like exercising. You avoid it. You groan about it. You think of a million other things you would rather do. Finally, you drag yourself to do it and you feel amazing. You vow that you will keep doing it over and over again and become a whole new super healthy glowing you. You approach Oprah-ish levels of inner calm and rejuvenation. And you may just feel so present that you forget about your plugged-in life altogether. It's a religious ritual that even an atheist can love.
"Shabbat and Zionism," Achad Ha'am 1898 [pre-statehood of Israel]
There is no need to be overly concerned with mitzvot (commandments) in order to know the value of Shabbat. Whoever feels in their heart a true connection with the life of the [Jewish] Nation in all generations, cannot in any way imagine a reality for the people of Israel without Shabbat. One could say, without any exaggeration, that more than Israel has kept Shabbat, Shabbat has kept Israel, and if it hadn't returned to them their souls and renewed the lives of their spirit each week, all the sufferings of the "days of creation" would drag us farther and farther downward, until they would eventually descend to the bottom floor of materialism, and ethical and intellectual baseness.