Jews observe the Sabbath in imitation of God who rested on the seventh day. Later rabbinical commentators noted that on the seventh day God finished the work of creation and then rested. His final creation according to this tradition is the Sabbath. Locating the origins of the Sabbath in the first Genesis creation story reminds us that God created the world and is Lord of creation. On the other six days we may work gaining mastery over the world, manipulating things, but on the seventh day we relinquish even the thought of such work or of anything, which would lessen the joy of Shabbat.
All productive activity is to be avoided on the Sabbath.
If the intent of the work involves mastery over nature through human intelligence and skill then it is a violation of the Sabbath. The Sabbath provides a weekly reminder that we are not the ultimate masters and mistresses over creation. Creation is a gift which God has entrusted to our stewardship. On one day we let go of even the desire to produce, to demonstrate mastery over creation, and acknowledge the One who is our true ruler, king of the universe, melekh ha-olam. Jewish tradition also links the Sabbath to the liberation of Israel from the bondage of Egypt.