Though many activities are forbidden on Shabbat–from writing to playing instruments–Shabbat is seen as a great gift from God to the Jewish people, and is celebrated with special songs, meals, and prayers.
The Sabbath (in Hebrew, Shabbat, pronounced shah-BAHT–or in some communities, Shabbos, “SHAH-bis”) may be Judaism’s most distinctive and characteristic practice, as well as one of its most pervasive and long-lasting gifts to Western civilization. A weekly 25-hour observance, from just before sundown each Friday through the completion of nightfall on Saturday, Shabbat is more than just a day off from labor. It is a day of physical and spiritual delights that is meant to illuminate certain key concepts in the traditional Jewish perception of the world.
Themes and Theology
Shabbat is portrayed in the Bible as the pinnacle of the creation of the universe, and its observance can be seen as a reminder of the purposefulness of the world and the role of human beings in it. Shabbat also serves as a memorial to God’s act of rescuing the Israelites from slavery in Egypt by setting aside a day for personal autonomy and freedom from the harsh demands of labor. The traditional Shabbat is portrayed in Jewish liturgy, song, and story as a day of joy, a sanctuary from travails, and even a foretaste of the perfected world that will someday be attained.
Material above excerpted from http://www.myjewishlearning.com/