Shabbat is a day of rest. However, it is not just a day to sleep late. The model of Sabbath rest can be found in Genesis 2:1-3: "The heaven and earth were finished, and all their array. On the seventh day God finished the work which God had been doing, and God ceased [rested] on the seventh day from all the work which God had done. And God blessed the seventh day and declared it holy, because on it god ceased [rested] from all the work of creation which God had done." Thus, the pattern of work and rest is woven into the very fabric of the universe. Rest means more than physical ceassation of work. It implies taking oneself out of the ordinary, out of the routine, out of the rat race. This kind of rest gives us the opportunity to re-create our spirit and restore our soul. Shabbat is a time that is set aside to take notice of the wonders around us.
Not only is the Sabbath an integral part of the Creation story, it is the only holiday mentioned in the Ten Commandments. The Ten Commandments actually appear twice in the Bible. The Sabbath commandment is formulated somewhat differently in each instance.
Remember the Sabbath day and keep it holy. Six days you shall labor and do all your work, but the seventh day is a Sabbath of Adonai your God: you shall not do any work - you, your son or daughter, your male or female slave, or your cattle, or the stranger who is within your settlements. For in six days, Adonai made heaven and earth and sea, all that is in them, and God rested on the seventh day; therefore Adonai has blessed the Sabbath day and hallowed it.
Observe the Sabbath day and keep it holy, as Adonai your God has commanded you. Six days you shall labor and do all your work, but the seventh day is a Sabbath of Adonai your God: you shall not do any work - you, your son or your daughter, your male or female slave, your ox of your ass, or any of your cattle, or the stranger in your settlements, so that your male and female slave may rest as you do. Remember that you were a slave in the land of Egypt and Adonai your God freed you from there with a mighty hand and an outstretched arm; therefore Adonai your God has commanded you to observe the sabbathday
These two passages point out two different aspects of Shabbat. Exodus tells us to remember the Sabbath while Deuteronomy stresses the observance of the day. Each passage offers us a different rationale for Shabbat. Exodus reminds us that on Shabbat we rejoice in the creation of the physical universe. Deuteronomy reminds us of our own experience of slavery and that we must remember our Exodus from Egypt. In doing so, we are cognizant of the freedom we enjoy.