and challah, a festive meal is served. Singing is traditional at Sabbath meals. In modern times, many composers have written sacred music for use during the Kabbalat Shabbat observance, including Robert Strassburg and Samuel Adler. According to rabbinic literature, God via the Torah commands Jews to observe (refrain from forbidden activity) and remember (with words, thoughts, and actions) Shabbat, and these two actions are symbolized by the customary two Shabbat candles. Candles are lit usually by the woman of the house (or else by a man who lives alone). Some families light more candles, sometimes in accordance with the number of children. Other rituals Shabbat is a day of celebration as well as prayer. It is customary to eat three festive meals: Dinner on Shabbat eve (Friday night), lunch on Shabbat day (Saturday), and a third meal (a Seudah shlishit) in the late afternoon (Saturday). It is also customary to wear nice clothing (different from during the week) on Shabbat to honor the day. Many Jews attend synagogue services on Shabbat even if they do not do so during the week. Services are held on Shabbat eve (Friday night), Shabbat morning (Saturday morning), and late Shabbat afternoon (Saturday afternoon). With the exception of Yom Kippur, days of public fasting are postponed or advanced if they coincide with Shabbat. Mourners sitting shivah (week of mourning subsequent to the death of a spouse or first-degree relative) outwardly conduct themselves normally for the duration of the day and are forbidden to display public signs of mourning. Although most Shabbat laws are restrictive, the fourth of the Ten Commandments in Exodus is taken by the Talmud and Maimonides to allude to the positive commandments of Shabbat. These include: Honoring Shabbat (kavod Shabbat): on Shabbat, wearing festive clothing and refraining from unpleasant conversation. It is customary to avoid talking on Shabbat about money, business matters, or secular things that one might discuss during the week. Recitation of kiddush over a cup of wine at the beginning of Shabbat meals, or at a reception after the conclusion of morning prayers (see the list of Jewish prayers and blessings). Eating three festive meals. Meals begin with a blessing over two loaves of bread (lechem mishneh, "double bread"), usually of braided challah, which is symbolic of the double portion of manna that fell for the Jewish people on the day before Sabbath during their 40 years in the