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).andles are lit at this time. It is customary in many communities to light the candles 18 minutes before sundown (tosefet Shabbat, though sometimes 36 minutes), and most printed Jewish calendars adhere to this custom.