V’shamru is taken from Exodus 31:16-17. Shabbat is created to give us rest and to restore the soul. “Vayinafash” is from the Hebrew word “nefesh” (soul). Shabbat is the promise that there will be a time of peace for all people. As God guards us, we guard Shabbat.
וְשָׁמְרוּ בְנֵי יִשְׂרָאֵל אֶת הַשַּׁבָּת, לַעֲשׂוֹת אֶת הַשַּׁבָּת לְדֹרֹתָם בְּרִית עוֹלָם. בֵּינִי וּבֵן בְּנֵי יִשׂרָאֵל אוֹת הִיא לְעֹלָם. כִּי שֵֽׁשֶׁת יָמִים עָשָׂה יהוה אֶת הַשָּׁמַיִם וְאֶת הָאֳרֶץ, וּבַיּוֹם הַשְּׁבִיעִי שָׁבַת וַיִּנָּפַשׁ.
V’shamru Vnei Yisrael et HaShabbat, laasot et HaShabbat l’dorotam b’rit olam. Beini u’vein b’nei Yisrael or hi l’olam, ki sheishet yamim asah Adonai et hashamayim v’et haaretz, u’vayom hasvi-i shavat vayinafash.
The children of Israel shall observe the Sabbath, observing the Sabbath throughout their generations as a covenant for all time. It is a sign forever between Me and people of Israel. For in six days the Eternal One made heaven and earth, and on the seventh day God ceased from work and rested.