Shabbat Image: Kiddush Cup, Candles, Challah, Siddur (Prayer Book)
Shabbat, or the Sabbath, is a day of rest and is celebrated every week from Friday night at sunset until Saturday night at sundown (25 hours). God ordered its observance in the Fourth Commandment, "Six days you shall labor and do all of your work, but the seventh day is a sabbath of God: you shall not do any work." (Exodus 20:9-10). On Shabbat, you spend time with family, pray, read, and rejuvenate. Many Jewish people light candles to symbolically ward off the darkness and welcome the Divine.

Also See: What is Shabbat and How is it Celebrated?
(from JOI's "Intermarriage Q&A")