Shabbat (also called Shabbos or Sabbath) is the Jewish day of rest that is observed once a week, from sundown on Friday until nightfall on Saturday (traditionally, after three stars can be seen on the sky).
The Hebrew meaning of the word Shabbat is "to cease", because on that day, God ceased his labour of creation. Thus, Shabbat is the day of ceasing from work. Shabbat does not mean "to rest" or "seventh day" as some may think.
With the exception of Yom Kippur, days of public fasting are postponed or advanced for a day if they coincide with Shabbat, and mourners sitting Shivah conduct themselves normally for the duration of the day and are indeed forbidden to express public signs of mourning.
The Observance of Shabbat is mentioned as the fourth of the Ten Commandments:
There are many other instances where the Sabbath is referred to.
The Shabbat biblical laws define what one should avoiod doing during the Sabbath. The traditions of the Shabbat evolved over the centuries, but are not directly founded in biblical texts. Some of the Shabbat traditions include:
Jews are commanded by God to keep and remember the Shabbat, and these two actions are represented by lighting two candles.
Recitation of Kiddush over a cup of wine (Kiddush Cup) in the evening and the morning, emphasizing the holiness of the day.
Three festive meals are eaten each Shabbat: on Friday night, Saturday afternoon, and early Saturday evening before the conclusion of the Shabbat. These meals minimally include bread (the traditional Challah loaves) and meat (according to most traditional views).
Recitation of Havdalah at the conclusion on Saturday night (over a Kiddush Cup, fragrant spices and a candle).
All Jews are encouraged to attend services at a synagogue during Shabbat, even if they would not normally do so on weekdays.